4,5,6,7-tetrahyroimidazo[4,5-c]pyridine compounds

ABSTRACT

The present invention relates to compounds of formula (I), 
                         
and their pharmaceutically acceptable salts, solvates, hydrates, geometrical isomers, tautomers, optical isomers or N-oxides, which are inhibitors of SSAO activity. The invention further relates to pharmaceutical compositions comprising these compounds and to the use of these compounds for the treatment of medical conditions wherein inhibition of SSAO activity is beneficial, such as inflammatory diseases and immune disorders.

RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 14/062,969 filedOct. 25, 2013, now U.S. Pat. No. 9,035,066, which is a continuation ofU.S. Ser. No. 13/567,146 filed Aug. 6, 2012, now U.S. Pat. No.8,569,338, which is a divisional of U.S. Ser. No. 13/062,318, now U.S.Pat. No. 8,263,616, issued Sep. 11, 2012, which is a National Stageapplication of PCT/EP2009/062011 filed Sep. 16, 2009, which applicationclaims priority from SE Application No. 0801979-6 filed Sep. 16, 2008and the benefit of U.S. Ser. No. 61/106,734 filed Oct. 20, 2008. Theabove applications are incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

The present invention relates to new4,5,6,7-tetrahydroimidazo[4,5-c]pyridine compounds of formula (I), whichare inhibitors of SSAO activity. The invention also relates topharmaceutical compositions comprising these compounds and to the use ofthese compounds in the treatment or prevention of medical conditionswherein inhibition of SSAO activity is beneficial, such as inflammatorydiseases and immune disorders.

BACKGROUND ART

Semicarbazide-sensitive amine oxidase (SSAO), otherwise known asVascular Adhesion Protein-1 (VAP-1) or Amine Oxidase, Copper Containing3 (AOC3), belongs to the copper-containing amine oxidase family ofenzymes (EC.1.4.3.6). Members of this enzyme family are sensitive toinhibition by semicarbazide and utilize cupric ion and protein-derivedtopa quinone (TPQ) cofactor in the oxidative deamination of primaryamines to aldehydes, hydrogen peroxide, and ammonia according to thefollowing reaction:R—CH₂—NH₂+O₂→R—CHO+H₂O₂+NH₃

Known substrates for human SSAO include endogenous methylamine andaminoacetone as well as some xenobiotic amines such as benzylamine[Lyles, Int. J. Biochem. Cell Biol. 1996, 28, 259-274; Klinman, Biochim.Biophys. Acta 2003, 1647(1-2), 131-137; Mátyus et al., Curr. Med. Chem.2004, 11(10), 1285-1298; O'Sullivan et al., Neurotoxicology 2004,25(1-2), 303-315]. In analogy with other copper-containing amineoxidases, DNA-sequence analysis and structure determination suggest thatthe tissue-bound human SSAO is a homodimeric glycoprotein consisting oftwo 90-100 kDa subunits anchored to the plasma membrane by a singleN-terminal membrane spanning domain [Morris et al., J. Biol. Chem. 1997,272, 9388-m 9392; Smith et al., J. Exp. Med. 1998, 188, 17-27; Airenneet al., Protein Science 2005, 14, 1964-1974; Jakobsson et al., ActaCrystallogr. D Biol. Crystallogr. 2005, 61(Pt 11), 1550-1562].

SSAO activity has been found in a variety of tissues including vascularand non-vascular smooth muscle tissue, endothelium, and adipose tissue[Lewinsohn, Braz. J. Med. Biol. Res. 1984, 17, 223-256; Nakos & Gossrau,Folia Histochem. Cytobiol. 1994, 32, 3-10; Yu et al., Biochem.Pharmacol. 1994, 47, 1055-1059; Castillo et al., Neurochem. Int. 1998,33, 415-423; Lyles & Pino, J. Neural. Transm. Suppl. 1998, 52, 239-250;Jaakkola et al., Am. J. Pathol. 1999, 155, 1953-1965; Morin et al., J.Pharmacol. Exp. Ther. 2001, 297, 563-572; Salmi & Jalkanen, TrendsImmunol. 2001, 22, 211-216]. In addition, SSAO protein is found in bloodplasma and this soluble form appears to have similar properties as thetissue-bound form [Yu et al., Biochem. Pharmacol. 1994, 47, 1055-1059;Kurkijärvi et al., J. Immunol. 1998, 161, 1549-1557]. It has recentlybeen shown that circulating human and rodent SSAO originates from thetissue-bound form [Göktürk et al., Am. J. Pathol. 2003, 163(5),1921-1928; Abella et al., Diabetologia 2004, 47(3), 429-438; Stolen etal., Circ. Res. 2004, 95(1), 50-57], whereas in other mammals theplasma/serum SSAO is also encoded by a separate gene called AOC4[Schwelberger, J. Neural. Transm. 2007, 114(6), 757-762].

The precise physiological role of this abundant enzyme has yet to befully determined, but it appears that SSAO and its reaction products mayhave several functions in cell signalling and regulation. For example,recent findings suggest that SSAO plays a role in both GLUT4-mediatedglucose uptake [Enrique-Tarancon et al., J. Biol. Chem. 1998, 273,8025-8032; Morin et al., J. Pharmacol. Exp. Ther. 2001, 297, 563-572]and adipocyte differentiation [Fontana et al., Biochem. J. 2001, 356,769-777; Mercier et al., Biochem. J. 2001, 358, 335-342]. In addition,SSAO has been shown to be involved in inflammatory processes where itacts as an adhesion protein for leukocytes [Salmi & Jalkanen, TrendsImmunol. 2001, 22, 211-216; Salmi & Jalkanen, in “Adhesion Molecules:Functions and Inhibition” K. Ley (Ed.), 2007, pp. 237-251], and mightalso play a role in connective tissue matrix development and maintenance[Langford et al., Cardiovasc. Toxicol. 2002, 2(2), 141-150; Göktürk etal., Am. J. Pathol. 2003, 163(5), 1921-1928]. Moreover, a link betweenSSAO and angiogenesis has recently been discovered [Noda et al., FASEBJ. 2008, 22(8), 2928-2935].

Several studies in humans have demonstrated that SSAO activity in bloodplasma is elevated in conditions such as congestive heart failure,diabetes mellitus, Alzheimer's disease, and inflammation [Lewinsohn,Braz. J. Med. Biol. Res. 1984, 17, 223-256; Boomsma et al., Cardiovasc.Res. 1997, 33, 387-391; Ekblom, Pharmacol. Res. 1998, 37, 87-92;Kurkijärvi et al., J. Immunol. 1998, 161, 1549-1557; Boomsma et al.,Diabetologia 1999, 42, 233-237; Meszaros et al., Eur. J. Drug Metab.Pharmacokinet. 1999, 24, 299-302; Yu et al., Biochim. Biophys. Acta2003, 1647(1-2), 193-199; Mátyus et al., Curr. Med. Chem. 2004, 11(10),1285-1298; O'Sullivan et al., Neurotoxicology 2004, 25(1-2), 303-315;del Mar Hernandez et al., Neurosci. Lett. 2005, 384(1-2), 183-187]. Themechanisms underlying these alterations of enzyme activity are notclear. It has been suggested that reactive aldehydes and hydrogenperoxide produced by endogenous amine oxidases contribute to theprogression of cardiovascular diseases, diabetic complications andAlzheimer's disease [Callingham et al., Prog. Brain Res. 1995, 106,305-321; Ekblom, Pharmacol. Res. 1998, 37, 87-92; Yu et al., Biochim.Biophys. Acta 2003, 1647(1-2), 193-199; Jiang et al., Neuropathol ApplNeurobiol. 2008, 34(2), 194-204]. Furthermore, the enzymatic activity ofSSAO is involved in the leukocyte extravasation process at sites ofinflammation where SSAO has been shown to be strongly expressed on thevascular endothelium [Salmi et al., Immunity 2001, 14(3), 265-276; Salmi& Jalkanen, in “Adhesion Molecules: Functions and Inhibition” K. Ley(Ed.), 2007, pp. 237-251]. Accordingly, inhibition of SSAO has beensuggested to have a therapeutic value in the prevention of diabeticcomplications and in inflammatory diseases [Ekblom, Pharmacol. Res.1998, 37, 87-92; Salmi et al., Immunity 2001, 14(3), 265-276; Salter-Cidet al., J. Pharmacol. Exp. Ther. 2005, 315(2), 553-562].

SSAO knockout animals are phenotypically overtly normal but exhibit amarked decrease in the inflammatory responses evoked in response tovarious inflammatory stimuli [Stolen et al., Immunity 2005, 22(1),105-115]. In addition, antagonism of its function in wild type animalsin multiple animal models of human disease (e.g. carrageenan-induced pawinflammation, oxazolone-induced colitis, lipopolysaccharide-induced lunginflammation, collagen-induced arthritis, endotoxin-induced uveitis) bythe use of antibodies and/or small molecules has been shown to beprotective in decreasing the leukocyte infiltration, reducing theseverity of the disease phenotype and reducing levels of inflammatorycytokines and chemokines [Kirton et al., Eur. J. Immunol. 2005, 35(11),3119-3130; Salter-Cid et al., J. Pharmacol. Exp. Ther. 2005, 315(2),553-562; McDonald et al., Annual Reports in Medicinal Chemistry 2007,42, 229-243; Salmi & Jalkanen, in “Adhesion Molecules: Functions andInhibition” K. Ley (Ed.), 2007, pp. 237-251; Noda et al., FASEB J. 200822(4), 1094-1103; Noda et al., FASEB J. 2008, 22(8), 2928-2935]. Thisanti-inflammatory protection seems to be afforded across a wide range ofinflammatory models all with independent causative mechanisms, ratherthan being restricted to one particular disease or disease model. Thiswould suggest that SSAO may be a key nodal point for the regulation ofthe inflammatory response, and it therefore seems likely that SSAOinhibitors may be effective anti-inflammatory drugs in a wide range ofhuman diseases.

The invention described here relates to noveltetrahydroimidazo[4,5-c]pyridine derivatives as a new class ofchemically distinct SSAO inhibitors with biological, pharmacological,and pharmacokinetic characteristics that make them suitable for use asprophylactic or therapeutic agents in a wide range of human inflammatorydiseases and immune disorders. This therapeutic capacity is designed toblock SSAO enzyme action, reducing the levels of pro-inflammatory enzymeproducts (aldehydes, hydrogen peroxide and ammonia) whilst alsodecreasing the adhesive capacity of immune cells and correspondinglytheir activation and final extra-vasation. Diseases where such anactivity is expected to be therapeutically beneficial include alldiseases where immune cells play a prominent role in the initiation,maintenance or resolution of the pathology, such as multiple sclerosis,arthritis and vasculitis.

WO 00/63208 discloses tetrahydroimidazo[4,5-c]pyridine derivatives withagonistic or antagonistic activity on the histamine H3 receptor for usein the treatment of eating disorders, obesity, diabetes andinflammation. EP 531874 shows tetrahydroimidazo[4,5-c]pyridinederivatives having angiotensin II inhibitory activity, which can be usedas hypotensive agents. U.S. Pat. No. 5,091,390 describestetrahydroimidazo-[4,5-c]pyridine-based angiotensin II receptorinhibitors that are useful for the treatment of CNS disorders. GB2028798 relates to tetrahydroimidazo[4,5-c]pyridine derivatives for thepreparation of antiulcer and anticholinergic compounds. WO 02/38153discloses the use of certain tetrahydroimidazo[4,5-c]pyridinederivatives as inhibitors of SSAO for the treatment of diabetes andvascular complications.

DISCLOSURE OF THE INVENTION

It has surprisingly been discovered that the SSAO inhibitory activity oftetrahydroimidazo[4,5-c]pyridine derivatives is drastically increased bythe presence of an isopropyl group in the 4-position of these compounds.Such compounds are therefore useful in the treatment or prevention ofdiseases in which inhibition of SSAO activity is beneficial. As suchthey are potentially useful for the treatment or prevention ofinflammation, inflammatory diseases, immune or autoimmune disorders.Consequently, the invention relates to a compound of formula (I),

or a pharmaceutically acceptable salt, solvate, hydrate, geometricalisomer, tautomer, optical isomer or N-oxide thereof, wherein:

R¹ is selected from:

-   -   (a) hydrogen,    -   (b) C₁₋₆-alkyl, and    -   (c) NR^(4A)R^(4B);

R² is selected from:

-   -   (a) hydrogen,    -   (b) C₁₋₆-alkyl,    -   (c) halo-C₁₋₆-alkyl,    -   (d) hydroxy-C₁₋₆-alkyl,    -   (e) C₁₋₆-alkoxy-C₁₋₆-alkyl,    -   (f) halo-C₁₋₆-alkoxy-C₁₋₆-alkyl,    -   (g) N(R^(4A)R^(4B))—C₁₋₆-alkyl,    -   (h) C(O)NR^(4A)R^(4B), and    -   (i) C(O)O—C₁₋₆-alkyl;

R³ is selected from:

-   -   (a) C₁₋₆-alkyl,    -   (b) halo-C₁₋₆-alkyl,    -   (c) hydroxy-C₁₋₆-alkyl,    -   (d) C₁₋₆-alkoxy-C₁₋₆-alkyl,    -   (e) halo-C₁₋₆-alkoxy-C₁₋₆-alkyl,    -   (f) N(R^(4A)R^(4B))—C₁₋₆-alkyl,    -   (g) C₆₋₁₀-aryl-C₁₋₄-alkyl,    -   (h) heteroaryl-C₁₋₄-alkyl,    -   (i) C₆₋₁₀-aryloxy-C₁₋₄-alkyl,    -   (j) heteroaryloxy-C₁₋₄-alkyl,    -   (k) C₃₋₈-cycloalkyl,    -   (l) C₃₋₈-cycloalkyl-C₁₋₄-alkyl,    -   (m) heterocyclyl, and    -   (n) heterocyclyl-C₁₋₄-alkyl,

wherein any aryl or heteroaryl residue is optionally substituted withone more substituents independently selected from halogen, hydroxy,cyano, nitro, CF₃, C₁₋₄-alkyl, C₁₋₄-alkoxy and NR^(4A)R^(4B), andwherein any cycloalkyl or heterocyclyl residue is optionally substitutedwith one or more substituents independently selected from halogen,hydroxy, C₁₋₄-alkyl, C₁₋₄-alkoxy and —NR^(4A)R^(4B);

R^(4A) and R^(4B) are each independently selected from:

-   -   (a) hydrogen,    -   (b) C₁₋₆-alkyl, and    -   (c) C₁₋₆-acyl.

In a preferred embodiment of the invention, R¹ is H.

R² is preferably selected from hydrogen, —C(O)O—C₁₋₆-alkyl and—C(O)NR^(4A)R^(4B).

More preferably, R² is selected from hydrogen, —C(O)O—C₁₋₃-alkyl and—C(O)NR^(4A′)R^(4B′), wherein R^(4A′) and R^(4B′) are independentlyselected from hydrogen and C₁₋₂-alkyl.

In a most preferred embodiment, R² is hydrogen, —C(O)OMe, —C(O)NH₂ or—C(O)NHMe.

R³ is preferably selected from halo-C₁₋₄-alkyl,halo-C₁₋₄-alkoxy-C₁₋₄-alkyl, di(C₁₋₄-alkyl)amino-C₁₋₄-alkyl,C₆₋₁₀-aryl-C₁₋₄-alkyl, C₆₋₁₀-aryloxy-C₁₋₄-alkyl, heteroaryl-C₁₋₄-alkyl,heteroaryloxy-C₁₋₄-alkyl, heterocyclyl and heterocyclyl-C₁₋₄-alkyl,wherein any aryl, heteroaryl or heterocyclyl residue is optionallysubstituted with one or two substituents independently selected fromhalogen and C₁₋₄-alkyl.

More preferably, R³ is selected from halo-C₁₋₂-alkyl,halo-C₁₋₂-alkoxy-C₁₋₂-alkyl, di(C₁₋₂-alkyl)amino-C₁₋₂-alkyl,phenyl-C₁₋₂-alkyl, phenoxy-C₁₋₂-alkyl, C₅₋₆-heteroaryl-C₁₋₂-alkyl,C₅₋₆-heteroaryloxy-C₁₋₂-alkyl, heterocyclyl and heterocyclyl-C₁₋₂-alkyl,and wherein any phenyl, heteroaryl or heterocyclyl residue is optionallysubstituted with one or two substituents independently selected fromhalogen and C₁₋₂-alkyl.

In a most preferred embodiment, R³ is 2,2,2-trichloroethyl,2-chloro-2,2-difluoroethyl, 2,2,2-trifluoroethoxyethyl,dimethylaminoethyl, benzyl, pyridinylmethyl, pyrazinylmethyl,thiazolylmethyl, isoxazolylmethyl, phenoxyethyl, pyridinyloxyethyl,tetrahydrofuranyl, tetrahydrofuranylmethyl, pyrrolidinyl,pyrrolidinylmethyl or oxetanylmethyl, and wherein any phenyl, heteroarylor heterocyclyl residue is optionally monosubstituted with halogen ormethyl.

Specific preferred compounds of formula (I) are the compounds selectedfrom the group consisting of:

-   2,2,2-Trichloroethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   2-Chloro-2,2-difluoroethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   Benzyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   3-Chlorobenzyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   4-Chlorobenzyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   Pyridin-2-ylmethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   Pyridin-3-ylmethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   Pyridin-4-ylmethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   (5-Chloropyridin-2-yl)methyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   Pyrazin-2-ylmethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   Benzyl    (4S,6S)-6-(aminocarbonyl)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo-[4,5-c]-pyridine-5-carboxylate;-   Benzyl    (4S,6S)-4-isopropyl-6-[(methylamino)carbonyl]-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   5-Benzyl    6-methyl(4S,6S)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5,6-dicarboxylate;-   2-Phenoxyethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   2-(4-Chlorophenoxyl)ethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   (3S)-Tetrahydrofuran-3-yl(4S)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   Tetrahydrofuran-3-ylmethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   (3-Methyloxetan-3-yl)methyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   2-(Dimethylamino)ethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   (2R)-Tetrahydrofuran-2-ylmethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]-pyridine-5-carboxylate;-   1,3-Thiazol-2-ylmethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   (5-Methylisoxazol-3-yl)methyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   [(2S)-1-Methylpyrrolidin-2-yl]methyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo-[4,5-c]pyridine-5-carboxylate;-   (3R)-1-methylpyrrolidin-3-yl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   Oxetan-2-ylmethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;-   2-(Pyridin-3-yloxy)ethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate;    and-   2-(2,2,2-Trifluoroethoxyl)ethyl    4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate.

Another object of the present invention is a compound of formula (I) foruse in therapy. The compounds as defined above are useful as inhibitorsof SSAO activity. As such, they are useful in the treatment orprevention of conditions and diseases in which inhibition of SSAOactivity is beneficial. More specifically, they are useful for thetreatment or prevention of inflammation, inflammatory diseases, immuneor autoimmune disorders.

In particular, it is believed that compounds of formula (I) are usefulfor the treatment or prevention of arthritis (such as rheumatoidarthritis, juvenile rheumatoid arthritis, osteoarthritis and psoriaticarthritis), synovitis, vasculitis, conditions associated withinflammation of the bowel (such as Crohn's disease, ulcerative colitis,inflammatory bowel disease and irritable bowel syndrome),atherosclerosis, multiple sclerosis, Alzheimer's disease, vasculardementia, pulmonary inflammatory diseases (such as asthma, chronicobstructive pulmonary disease and acute respiratory distress syndrome),fibrotic diseases (including idiopathic pulmonary fibrosis, cardiacfibrosis and systemic sclerosis (scleroderma)), inflammatory diseases ofthe skin (such as contact dermatitis, atopic dermatitis and psoriasis),systemic inflammatory response syndrome, sepsis, inflammatory and/orautoimmune conditions of the liver (such as autoimmune hepatitis,primary biliary cirrhosis, alcoholic liver disease, sclerosingcholangitis, and autoimmune cholangitis), diabetes (type I or II) and/orthe complications thereof, chronic heart failure, congestive heartfailure, ischemic diseases (such as stroke and ischemia-reperfusioninjury), and myocardial infarction and/or the complications thereof.

It is believed that the compounds of the invention are especially usefulfor the treatment or prevention of vasculitis, including, but notlimited to, giant cell arteritis, Takayasu's arteritis, Polyarteritisnodosa, Kawasaki disease, Wegener's granulomatosis, Churg-Strausssyndrome, microscopic polyangiitis, Henoch-Schölein purpura,cryoglobulinemia, cutaneous leukocytoclastic angiitis and primaryangiitis of the central nervous system.

The invention thus includes the use of said compounds in the manufactureof a medicament for the treatment or prevention of the above-mentionedconditions and diseases. The invention also includes methods fortreatment or prevention of such conditions and diseases, comprisingadministering to a mammal, including man, in need of such treatment aneffective amount of a compound as defined above.

Methods delineated herein include those wherein the subject isidentified as in need of a particular stated treatment. Identifying asubject in need of such treatment can be in the judgment of a subject ora health care professional and can be subjective (e.g. opinion) orobjective (e.g. measurable by a test or diagnostic method).

In other aspects, the methods herein include those further comprisingmonitoring subject response to the treatment administrations. Suchmonitoring may include periodic sampling of subject tissue, fluids,specimens, cells, proteins, chemical markers, genetic materials, etc. asmarkers or indicators of the treatment regimen. In other methods, thesubject is pre-screened or identified as in need of such treatment byassessment for a relevant marker or indicator of suitability for suchtreatment.

In one embodiment, the invention provides a method of monitoringtreatment progress. The method includes the step of determining a levelof diagnostic marker (Marker) (e.g., any target or cell type delineatedherein modulated by a compound herein) or diagnostic measurement (e.g.,screen, assay) in a subject suffering from or susceptible to a disorderor symptoms thereof delineated herein, in which the subject has beenadministered a therapeutic amount of a compound herein sufficient totreat the disease or symptoms thereof. The level of Marker determined inthe method can be compared to known levels of Marker in either healthynormal controls or in other afflicted patients to establish thesubject's disease status. In preferred embodiments, a second level ofMarker in the subject is determined at a time point later than thedetermination of the first level, and the two levels are compared tomonitor the course of disease or the efficacy of the therapy. In certainpreferred embodiments, a pre-treatment level of Marker in the subject isdetermined prior to beginning treatment according to this invention;this pre-treatment level of Marker can then be compared to the level ofMarker in the subject after the treatment commences, to determine theefficacy of the treatment.

In certain method embodiments, a level of Marker or Marker activity in asubject is determined at least once. Comparison of Marker levels, e.g.,to another measurement of Marker level obtained previously orsubsequently from the same patient, another patient, or a normalsubject, may be useful in determining whether therapy according to theinvention is having the desired effect, and thereby permittingadjustment of dosage levels as appropriate. Determination of Markerlevels may be performed using any suitable sampling/expression assaymethod known in the art or described herein. Preferably, a tissue orfluid sample is first removed from a subject.

Examples of suitable samples include blood, urine, tissue, mouth orcheek cells, and hair samples containing roots. Other suitable sampleswould be known to the person skilled in the art. Determination ofprotein levels and/or mRNA levels (e.g., Marker levels) in the samplecan be performed using any suitable technique known in the art,including, but not limited to, enzyme immunoassay, ELISA,radiolabeling/as say techniques, blotting/chemiluminescence methods,real-time PCR, and the like.

DEFINITIONS

The following definitions shall apply throughout the specification andthe appended claims.

Unless otherwise stated or indicated, the term “C₁₋₆-alkyl” denotes astraight or branched alkyl group having from 1 to 6 carbon atoms. Forparts of the range “C₁₋₆-alkyl” all subgroups thereof are contemplatedsuch as C₁₋₅-alkyl, C₁₋₄-alkyl, C₁₋₃-alkyl, C₁₋₂-alkyl, C₂₋₆-alkyl,C₂₋₅-alkyl, C₂₋₄-alkyl, C₂₋₃-alkyl, C₃₋₆-alkyl, C₄₋₅-alkyl, etc.Examples of said “C₁₋₆-alkyl” include methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl and straight- andbranched-chain pentyl and hexyl.

Unless otherwise stated or indicated, the term “halo-C₁₋₆-alkyl” denotesa straight or branched C₁₋₆-alkyl group substituted by one or morehalogen atoms. The term halo-C₁₋₆-alkyl includes fluoro-C₁₋₆-alkyl,chloro-C₁₋₆-alkyl, bromo-C₁₋₆-alkyl and iodo-C₁₋₆-alkyl. Examples ofsaid halo-C₁₋₆-alkyl include 2-fluoroethyl, fluoromethyl, chloromethyl,trifluoromethyl, trichloromethyl, 2,2,2-trifluoroethyl,2,2,2-trichloroethyl and 2-chloro-2,2-difluoroethyl.

Unless otherwise stated or indicated, the term “hydroxy-C₁₋₆-alkyl”denotes a straight or branched C₁₋₆-alkyl group that has a hydrogen atomthereof replaced with OH. Examples of said hydroxy-C₁₋₆-alkyl includehydroxymethyl, 2-hydroxyethyl, 2-hydroxypropyl and2-hydroxy-2-methylpropyl.

The derived expression “C₁₋₆-alkoxy” is to be construed accordinglywhere a C₁₋₆-alkyl group is attached to the remainder of the moleculethrough an oxygen atom. For parts of the range “C₁₋₆-alkoxy” allsubgroups thereof are contemplated such as C₁₋₅-alkoxy, C₁₋₄-alkoxy,C₁₋₃-alkoxy, C₁₋₂-alkoxy, C₂₋₆-alkoxy, C₂₋₅-alkoxy, C₂₋₄-alkoxy,C₂₋₃-alkoxy, C₃₋₆-alkoxy, C₄₋₅-alkoxy, etc. Examples of said“C₁₋₆-alkoxy” include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy,isobutoxy, sec-butoxy, t-butoxy and straight- and branched-chain pentoxyand hexoxy etc.

Unless otherwise stated or indicated, the term “C₁₋₆-alkoxy-C₁₋₆-alkyl”refers to a straight or branched C₁₋₆-alkoxy group that is bonded to astraight or branched C₁₋₆-alkyl group via an oxygen atom of saidC₁₋₆-alkoxy group. Representative examples of such groups includemethoxymethyl and ethoxyethyl.

Unless otherwise stated or indicated, the term“halo-C₁₋₆-alkoxy-C₁₋₆-alkyl” refers to a C₁₋₆-alkoxy-C₁₋₆-alkyl groupwherein the C₁₋₆-alkoxy group is substituted by one or more halogenatoms. Examples of said halo-C₁₋₆-alkoxy-C₁₋₆-alkyl include2,2,2-trifluoroethoxyethyl and trifluoromethoxyethyl.

Unless otherwise stated or indicated, the term “C₁₋₆-acyl” denotes acarbonyl group that is attached through its carbon atom to a hydrogenatom (i.e., a formyl group) or to a straight or branched C₁₋₅-alkylgroup, where alkyl is defined as above. For parts of the range“C₁₋₆-acyl” all subgroups thereof are contemplated such as C₁₋₅-acyl,C₁₋₄-acyl, C₁₋₃-acyl, C₁₋₂-acyl, C₂₋₆-acyl, C₂₋₅-acyl, C₂₋₄-acyl,C₂₋₃-acyl, C₃₋₆-acyl, C₄₋₅-acyl, etc. Exemplary acyl groups includeformyl, acetyl, propanoyl, butanoyl, pentanoyl, hexanoyl.

Unless otherwise stated or indicated, the term “C₆₋₁₀-aryl” refers to amonocyclic or fused bicyclic hydrocarbon ring system comprising 6 to 10ring atoms and wherein at least one ring is an aromatic ring. Examplesof C₆₋₁₀-aryl groups are phenyl, indenyl, 2,3-dihydroindenyl (indanyl),1-naphthyl, 2-naphthyl or 1,2,3,4-tetrahydronaphthyl.

Unless otherwise stated or indicated, the term “C₆₋₁₀-aryl-C₁₋₄-alkyl”refers to a C₆₋₁₀-aryl group that is directly linked to a straight orbranched C₁₋₄-alkyl group. Examples of such groups include phenylmethyl(i.e., benzyl) and phenylethyl.

Unless otherwise stated or indicated, the term“C₆₋₁₀-aryloxy-C₁₋₄-alkyl” refers to a C₆₋₁₀-aryl group that is linkedto a straight or branched C₁₋₄-alkyl group via a bridging oxygen atom.

Examples of such groups include phenoxymethyl and phenoxyethyl.

Unless otherwise stated or indicated, the term “heteroaryl” refers to amonocyclic or fused bicyclic heteroaromatic ring system comprising 5 to10 ring atoms in which one or more of the ring atoms are other thancarbon, such as nitrogen, sulphur or oxygen. Only one ring need to bearomatic and said heteroaryl moiety can be linked to the remainder ofthe molecule via a carbon or nitrogen atom in any ring. Examples ofheteroaryl groups include furyl, pyrrolyl, thienyl, oxazolyl,isoxazolyl, imidazolyl, thiazolyl, isothiazolyl, pyridinyl, pyrimidinyl,tetrazolyl, quinazolinyl, indolyl, indolinyl, isoindolyl, isoindolinyl,pyrazolyl, pyridazinyl, pyrazinyl, quinolinyl, quinoxalinyl,thiadiazolyl, benzofuranyl, 2,3-dihydrobenzofuranyl, 1,3-benzodioxolyl,1,4-benzodioxinyl, 2,3-dihydro-1,4-benzodioxinyl, benzothiazolyl,benzimidazolyl, benzothiadiazolyl, benzotriazolyl and chromanyl.

Unless otherwise stated or indicated, the term “heteroaryl-C₁₋₄-alkyl”refers to a heteroaryl group that is directly linked to a straight orbranched C₁₋₄-alkyl group via a carbon or nitrogen atom of said ringsystem. Examples of such groups include pyridinylmethyl,pyrazinylmethyl, thiazolylmethyl and isoxazolylmethyl.

Unless otherwise stated or indicated, the term“heteroaryloxy-C₁₋₄-alkyl” refers to a heteroaryl group that is linkedto a straight or branched C₁₋₄-alkyl group via a bridging oxygen atom.Examples of such groups include pyridinyloxyethyl andpyrazinyloxymethyl.

Unless otherwise stated or indicated, the term “C₃₋₈-cycloalkyl” refersto a mono- or bicyclic, saturated or partially unsaturated hydrocarbonring system having from 3 to 8 carbon atoms. Bicyclic ring systems canbe either fused or bridged. In a bridged cycloalkyl ring system, twonon-adjacent carbon atoms of a monocyclic ring are linked by an alkylenebridge of between one and three additional carbon atoms. Examples ofsaid C₃₋₈-cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cyclohexenyl, cycloheptyl, cycloheptenyl and cyclooctyl, aswell as bicyclo[2.2.1]heptyl, bicyclo[2.2.2]octyl andbicyclo[3.2.1]octyl. For parts of the range “C₃₋₈-cycloalkyl” allsubgroups thereof are contemplated such as C₃₋₇-cycloalkyl,C₅₋₇-cycloalkyl, C₃₋₅-cycloalkyl, C₃₋₄-cycloalkyl, C₄₋₈-cycloalkyl,C₄₋₇-cycloalkyl, C₄₋₆-cycloalkyl, C₄₋₅-cycloalkyl, C₅₋₈-cycloalkyl,C₅₋₇-cycloalkyl, C₅₋₆-cycloalkyl, C₆₋₈-cycloalkyl and C₆₋₇-cycloalkyl.

Unless otherwise stated or indicated, the term“C₃₋₈-cycloalkyl-C₁₋₄-alkyl” refers to a C₃₋₈-cycloalkyl group that isdirectly attached to a straight or branched C₁₋₄-alkyl group. Examplesof C₃₋₈-cycloalkyl-C₁₋₄-alkyl groups include cyclopentylmethyl andcyclohexylethyl.

Unless otherwise stated or indicated, the term “heterocyclyl” or“heterocyclic ring” refers to a non-aromatic, fully saturated orpartially unsaturated, preferably fully saturated, monocyclic ringsystem having 4 to 7 ring atoms with at least one heteroatom such as O,N, or S, and the remaining ring atoms are carbon. Examples ofheterocyclic rings include piperidinyl, tetrahydropyranyl,tetrahydrofuranyl, oxetanyl, azepinyl, azetidinyl, pyrrolidinyl,morpholinyl, imidazolinyl, imidazolidinyl, thiomorpholinyl, pyranyl,dioxanyl, piperazinyl, homopiperazinyl and5,6-dihydro-4H-1,3-oxazin-2-yl. When present, the sulfur atom may be inan oxidized form (i.e., S═O or O═S═O). Exemplary heterocyclic groupscontaining sulfur in oxidized form are 1,1-dioxido-thiomorpholinyl and1,1-dioxido-isothiazolidinyl.

Unless otherwise stated or indicated, the term “heterocyclyl-C₁₋₄-alkyl”refers to a heterocyclic ring that is directly attached to a straight orbranched C₁₋₄-alkyl group via a carbon or nitrogen atom of said ringsystem. Examples of heterocyclyl-C₁₋₄-alkyl groups includeoxetanylmethyl, tetrahydrofuranylmethyl and pyrrolidinylmethyl.

“Halogen” refers to fluorine, chlorine, bromine or iodine.

“Hydroxy” refers to the —OH radical.

“Nitro” refers to the —NO₂ radical.

“Cyano” refers to the —CN radical.

“Optional” or “optionally” means that the subsequently described eventor circumstance may but need not occur, and that the descriptionincludes instances where the event or circumstance occurs and instancesin which it does not.

“Pharmaceutically acceptable” means being useful in preparing apharmaceutical composition that is generally safe, non-toxic and neitherbiologically nor otherwise undesirable and includes being useful forveterinary use as well as human pharmaceutical use.

“Treatment” as used herein includes prophylaxis of the named disorder orcondition, or amelioration or elimination of the disorder once it hasbeen established.

“An effective amount” refers to an amount of a compound that confers atherapeutic effect on the treated subject. The therapeutic effect may beobjective (i.e., measurable by some test or marker) or subjective (i.e.,subject gives an indication of or feels an effect).

“Prodrugs” refers to compounds that may be converted under physiologicalconditions or by solvolysis to a biologically active compound of theinvention. A prodrug may be inactive when administered to a subject inneed thereof, but is converted in vivo to an active compound of theinvention. Prodrugs are typically rapidly transformed in vivo to yieldthe parent compound of the invention, e.g. by hydrolysis in the blood.The prodrug compound usually offers advantages of solubility, tissuecompatibility or delayed release in a mammalian organism (see Silverman,R. B., The Organic Chemistry of Drug Design and Drug Action, 2^(nd) Ed.,Elsevier Academic Press (2004), pp. 498-549). Prodrugs of a compound ofthe invention may be prepared by modifying functional groups, such as ahydroxy, amino or mercapto groups, present in a compound of theinvention in such a way that the modifications are cleaved, either inroutine manipulation or in vivo, to the parent compound of theinvention. Examples of prodrugs include, but are not limited to,acetate, formate and succinate derivatives of hydroxy functional groupsor phenyl carbamate derivatives of amino functional groups.

Throughout the specification and the appended claims, a given chemicalformula or name shall also encompass all salts, hydrates, solvates,N-oxides and prodrug forms thereof. Further, a given chemical formula orname shall encompass all tautomeric and stereoisomeric forms thereof.Stereoisomers include enantiomers and diastereomers. Enantiomers can bepresent in their pure forms, or as racemic (equal) or unequal mixturesof two enantiomers. Diastereomers can be present in their pure forms, oras mixtures of diastereomers. Diastereomers also include geometricalisomers, which can be present in their pure cis or trans forms or asmixtures of those.

The compounds of formula (I) may be used as such or, where appropriate,as pharmacologically acceptable salts (acid or base addition salts)thereof. The pharmacologically acceptable addition salts mentioned beloware meant to comprise the therapeutically active non-toxic acid and baseaddition salt forms that the compounds are able to form. Compounds thathave basic properties can be converted to their pharmaceuticallyacceptable acid addition salts by treating the base form with anappropriate acid. Exemplary acids include inorganic acids, such ashydrogen chloride, hydrogen bromide, hydrogen iodide, sulphuric acid,phosphoric acid; and organic acids such as formic acid, acetic acid,propanoic acid, hydroxyacetic acid, lactic acid, pyruvic acid, glycolicacid, maleic acid, malonic acid, oxalic acid, benzenesulphonic acid,toluenesulphonic acid, methanesulphonic acid, trifluoroacetic acid,fumaric acid, succinic acid, malic acid, tartaric acid, citric acid,salicylic acid, p-aminosalicylic acid, pamoic acid, benzoic acid,ascorbic acid and the like. Exemplary base addition salt forms are thesodium, potassium, calcium salts, and salts with pharmaceuticallyacceptable amines such as, for example, ammonia, alkylamines,benzathine, and amino acids, such as, e.g. arginine and lysine. The termaddition salt as used herein also comprises solvates which the compoundsand salts thereof are able to form, such as, for example, hydrates,alcoholates and the like.

Compositions

For clinical use, the compounds of the invention are formulated intopharmaceutical formulations for various modes of administration. It willbe appreciated that compounds of the invention may be administeredtogether with a physiologically acceptable carrier, excipient, ordiluent. The pharmaceutical compositions of the invention may beadministered by any suitable route, preferably by oral, rectal, nasal,topical (including buccal and sublingual), sublingual, transdermal,intrathecal, transmucosal or parenteral (including subcutaneous,intramuscular, intravenous and intradermal) administration.

Other formulations may conveniently be presented in unit dosage form,e.g., tablets and sustained release capsules, and in liposomes, and maybe prepared by any methods well known in the art of pharmacy.Pharmaceutical formulations are usually prepared by mixing the activesubstance, or a pharmaceutically acceptable salt thereof, withconventional pharmaceutically acceptable carriers, diluents orexcipients. Examples of excipients are water, gelatin, gum arabicum,lactose, microcrystalline cellulose, starch, sodium starch glycolate,calcium hydrogen phosphate, magnesium stearate, talcum, colloidalsilicon dioxide, and the like. Such formulations may also contain otherpharmacologically active agents, and conventional additives, such asstabilizers, wetting agents, emulsifiers, flavouring agents, buffers,and the like. Usually, the amount of active compounds is between 0.1-95%by weight of the preparation, preferably between 0.2-20% by weight inpreparations for parenteral use and more preferably between 1-50% byweight in preparations for oral administration.

The formulations can be further prepared by known methods such asgranulation, compression, microencapsulation, spray coating, etc. Theformulations may be prepared by conventional methods in the dosage formof tablets, capsules, granules, powders, syrups, suspensions,suppositories or injections. Liquid formulations may be prepared bydissolving or suspending the active substance in water or other suitablevehicles. Tablets and granules may be coated in a conventional manner.To maintain therapeutically effective plasma concentrations for extendedperiods of time, compounds of the invention may be incorporated intoslow release formulations.

The dose level and frequency of dosage of the specific compound willvary depending on a variety of factors including the potency of thespecific compound employed, the metabolic stability and length of actionof that compound, the patient's age, body weight, general health, sex,diet, mode and time of administration, rate of excretion, drugcombination, the severity of the condition to be treated, and thepatient undergoing therapy. The daily dosage may, for example, rangefrom about 0.001 mg to about 100 mg per kilo of body weight,administered singly or multiply in doses, e.g. from about 0.01 mg toabout 25 mg each. Normally, such a dosage is given orally but parenteraladministration may also be chosen.

Preparation of Compounds of the Invention

The compounds of formula (I) above may be prepared by, or in analogywith, conventional methods. The preparation of intermediates andcompounds according to the examples of the present invention may inparticular be illuminated by the following Scheme 1. Definitions ofvariables in the structures in schemes herein are commensurate withthose of corresponding positions in the formulae delineated herein.

wherein R¹, R² and R³ are as defined in formula (I).

A key intermediate in the synthesis of compounds of the invention is the4-isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine derivative offormula (III), which can suitably be prepared by the condensation of theappropriate histamine derivative (II) with isobutyraldehyde. Compoundsof formula (I) can then easily be obtained by installing the urethanelinker containing R³ onto this intermediate (III). Typically theurethane linkers incorporated into compounds of formula (I) have beensynthesised utilising 4-nitrophenyl chloroformate as the activatingagent, but other activating agents can also be used for this purpose.Such agents include, but are not limited to, e.g. phosgene to formalcohol chloroformates, or carbonyldiimidazole (CDI) to form imidazolecarboylates.

In one process, the appropriate alcohol R³OH is activated bytransformation into the corresponding 4-nitrophenyl carbonate derivative(IV). The intermediate (III) is then treated with this carbonate (IV) inthe presence of a base (e.g., DIPEA, NMM or triethylamine) to give thedesired compound of formula (I).

In another process, intermediate (III) is first transformed into itscorresponding 4-nitrophenyl carbamate by treatment with 4-nitrophenylchloroformate. The activated carbamate (V) is then subsequently treatedwith the appropriate alcohol R³OH to give the desired compound offormula (I).

The formation of the urethane functionality is typically a two stepprocess but this may also be performed in a one-pot reaction byformation of the activated intermediate in situ. In such a process, thealcohol R³OH and 4-nitrophenyl chloroformate are first allowed to reactin the presence of a base (e.g., DIPEA, NMM or triethylamine), afterwhich intermediate (III) is added to the reaction mixture.

All of these alternatives are exemplified in the experimental sectionbelow.

Appropriate reaction conditions for the individual reaction steps areknown to a person skilled in the art. Particular reaction conditions forexamples of the invention are also described in the experimentalsection.

The necessary starting materials for preparing the compounds of formula(I) are either commercially available, or may be prepared methods knownin the art.

The processes described below in the experimental section may be carriedout to give a compound of the invention in the form of a free base or asan acid addition salt. A pharmaceutically acceptable acid addition saltmay be obtained by dissolving the free base in a suitable organicsolvent and treating the solution with an acid, in accordance withconventional procedures for preparing acid addition salts from basecompounds. Examples of addition salt forming acids are mentioned above.

The compounds of formula (I) may possess one or more chiral carbonatoms, and they may therefore be obtained in the form of opticalisomers, e.g., as a pure enantiomer, or as a mixture of enantiomers(racemate) or as a mixture containing diastereomers. The separation ofmixtures of optical isomers to obtain pure enantiomers is well known inthe art and may, for example, be achieved by fractional crystallizationof salts with optically active (chiral) acids or by chromatographicseparation on chiral columns.

The chemicals used in the synthetic routes delineated herein mayinclude, for example, solvents, reagents, catalysts, and protectinggroup and deprotecting group reagents. Examples of protecting groups aret-butoxycarbonyl (Boc), benzyl and trityl(triphenylmethyl). The methodsdescribed above may also additionally include steps, either before orafter the steps described specifically herein, to add or remove suitableprotecting groups in order to ultimately allow synthesis of thecompounds. In addition, various synthetic steps may be performed in analternate sequence or order to give the desired compounds. Syntheticchemistry transformations and protecting group methodologies (protectionand deprotection) useful in synthesizing applicable compounds are knownin the art and include, for example, those described in R. Larock,Comprehensive Organic Transformations, VCH Publishers (1989); T. W.Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 3^(rd)Ed., John Wiley and Sons (1999); L. Fieser and M. Fieser, Fieser andFieser's Reagents for Organic Synthesis, John Wiley and Sons (1994); andL. Paquette, ed., Encyclopedia of Reagents for Organic Synthesis, JohnWiley and Sons (1995) and subsequent editions thereof.

The following abbreviations have been used:

Ac Acetate

Aq Aqueous

d Day

DCM Dichloromethane

DIPEA Diisopropylethylamine

DMAP Dimethylaminopyridine

DMF N,N′-Dimethylformamide

EDC 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide

ee Enantiomeric excess

ES⁺ Electrospray

h Hour(s)

HBTU O-Benzotriazol-1-yl-N,N,N′,N′-tetramethyluroniumhexafluorophosphate

HOBt N-Hydroxybenzotriazole

HPLC High performance liquid chromatography

HRMS High resolution mass spectrometry

LCMS Liquid chromatography mass spectrometry

M Molar

[MH⁺] Protonated molecular ion

min Minutes

NMM N-methyl morpholine

NMR Nuclear magnetic resonance

RP Reverse phase

MS Mass spectrometry

R_(T) Retention time

sat Saturated

sec Seconds

THF Tetrahydrofuran

TFA Trifluoroacetic acid

TMS Tetramethylsilane

The recitation of a listing of chemical groups in any definition of avariable herein includes definitions of that variable as any singlegroup or combination of listed groups. The recitation of an embodimentherein includes that embodiment as any single embodiment or incombination with any other embodiments or portions thereof.

The invention will now be further illustrated by the followingnon-limiting examples. The specific examples below are to be construedas merely illustrative, and not limitative of the remainder of thedisclosure in any way whatsoever. Without further elaboration, it isbelieved that one skilled in the art can, based on the descriptionherein, utilize the present invention to its fullest extent. Allreferences and publications cited herein are hereby incorporated byreference in their entirety.

EXAMPLES AND INTERMEDIATE COMPOUNDS Experimental Methods

All reagents were commercial grade and were used as received withoutfurther purification, unless otherwise specified. Reagent grade solventswere used in all cases. 1H Nuclear magnetic resonance (NMR) was recordedon a Bruker DPX-400 spectrometer at 400 MHz. All spectra were recordedusing residual solvent or tetramethylsilane (TMS) as internal standard.Analytical LCMS was performed on a Waters ZQ mass spectrometer connectedto an Agilent 1100 HPLC system. Analytical HPLC was performed on anAgilent 1100 system. High-resolution mass spectra (HRMS) were obtainedon an Agilent MSD-TOF connected to an Agilent 1100 HPLC system. Duringthe analyses the calibration was checked by two masses and automaticallycorrected when needed. Spectra are acquired in positive electrospraymode. The acquired mass range was m/z 100-1100. Profile detection of themass peaks was used. Flash chromatography was performed on either aCombiFlash Companion system equipped with RediSep silica columns or aFlash Master Personal system equipped with Strata SI-1 silica gigatubes.Reverse Phase HPLC was performed on a Gilson system (Gilson 322 pumpwith Gilson 321 equilibration pump and Gilson 215 autosampler) equippedwith Phenomenex Synergi Hydro RP 150×10 mm, YMC ODS-A 100/150×20 mm orChirobiotic T 250×10 mm columns. Reverse phase column chromatography wasperformed on a Gilson system (Gilson 321 pump and Gilson FC204 fractioncollector) equipped with Merck LiChroprep® RP-18 (40-63 μm) silicacolumns. Microwave irradiations were carried out using a Biotagemicrowave. The compounds were automatically named using ACD 6.0. Allcompounds were dried in a vacuum oven overnight.

Analytical HPLC and LCMS data were obtained with:

System A: Phenomenex Synergi Hydro RP (C18, 30×4.6 mm, 4 μm), gradient5-100% CH₃CN (+0.085% TFA) in water (+0.1% TFA), 1.5 mL/min, with agradient time of 1.75 min, 200 nm, 30° C.; or

System B: Phenomenex Synergi Hydro RP (C18, 150×4.6 mm, 4 μm), gradient5-100% CH₃CN (+0.085% TFA) in water (+0.1% TFA), 1.5 mL/min with agradient time of 7 min, 200 nm, 30° C.

Chiral HPLC data were obtained with:

System C: Chirobiotic V polar ionic mode (150×4.6 mm), 70% MeOH in 10 mMaq ammonium formate buffer, 1.0 mL/min, over 10 min, 200 nm, 30° C.

Intermediate 1 4-Isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridinehydrochloride

Histamine dihydrochloride (61.9 g, 336 mmol) was dissolved in a solutionof NaOH (33.6 g, 841 mmol) in water (125 mL) and MeOH (500 mL), andisobutyraldehyde (61.4 mL, 672 mmol) was added. The reaction mixture washeated under reflux at 80° C. for 24 h, cooled to room temperature, thepH was adjusted to 7 with 1 M aq HCl solution (250 mL) and the solventswere removed in vacuo. The residue was dissolved in warm MeOH (300 mL),allowed to stand for 1 h, filtered and the solvents were removed invacuo. The residue was stirred in MeOH (50 mL) and acetone (400 mL) for2 h and was cooled to 4° C. for 2 h. The resulting precipitate wasfiltered and washed with acetone (100 mL) to give4-isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine hydrochloride(33.0 g, 48.7%) as a white solid.

Analytical LCMS: purity >90% (System A, R_(T)=0.51 min), ES⁺: 166.4[MH]⁺.

Intermediate 2 4-Nitrophenyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

Intermediate 1 (2.78 g, 8.28 mmol, 60% pure) and DIPEA (5.27 mL, 30.3mmol) were dissolved in DCM (100 mL). The reaction mixture was cooled to0° C. and 4-nitrophenyl chloroformate (4.07 g, 20.2 mmol) was added. Thereaction mixture was stirred at room temperature for 18 h. The reactionmixture was washed with sat aq NaHCO₃ solution (5×100 mL), dried (MgSO₄)and the solvents were removed in vacuo to give 4-nitrophenyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(5.28 g, crude) as a yellow gum.

Analytical HPLC: purity 41% (System B, R_(T)=4.70 min); Analytical LCMS:purity 86% (System A, R_(T)=1.70 min), ES⁺: 331.0 [MH]⁺.

Intermediate 3(4S,6S)-4-Isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylicacid

L-Histidine (10.0 g, 43.8 mmol) was dissolved in a solution of NaOH(7.73 g, 193 mmol) in water (25 mL) and MeOH (100 mL), andisobutyraldehyde (11.8 mL, 129 mmol) was added. The reaction mixture washeated under reflux at 80° C. for 24 h. The pH was adjusted to 7 with 1M aq HCl solution and the solvents were removed in vacuo. The residuewas dissolved in hot EtOH and cooled to room temperature. Theprecipitate was removed by filtration and the mother liquor concentratedin vacuo, washed with acetone (100 mL) and dried to give4-isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylicacid as a pale yellow solid (18.6 g, crude, 6:1 mixture of(4S,6S):(4R,6S) diastereoisomers).

1H NMR (400 MHz, CDCl₃) (diastereomers D1 and D2 observed in a 6:1ratio): δ_(H) 3.96 (1H, m, D1), 3.93 (1H, br d, J 6.5 Hz, D2), 3.84 (1H,dd, J 8.2 and 5.3 Hz, D2), 3.49 (1H, dd, J 11.1 and 4.2 Hz, D1), 3.05(1H, dd, J 15.8 and 5.3 Hz, D2), 3.01 (1H, ddd, J 15.4, 4.2 and 1.7 Hz,D1), 2.92 (1H, ddd, J 15.8, 8.2 and 0.9 Hz, D2), 2.72 (1H, ddd, J 15.4,11.1 and 2.5 Hz, D1), 2.38 (1H, m, D1) and 2.19 (1H, m, D2).

The relative stereochemistry of the major diastereoisomer was determinedto be cis by 1H NMR nOe experiments.

Intermediate 4(4S,6S)-5-[(Benzyloxy)carbonyl]-4-isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]-pyridine-6-carboxylicacid

Intermediate 3 (8.60 g, 47.8 mmol) was dissolved in Et₂O (25 mL) and 2 Maq NaOH solution (82 mL, 164 mmol) and the reaction mixture was cooledto 0° C. Benzyl chloroformate (12.9 mL, 90.4 mmol) was added and thereaction mixture was warmed to room temperature over 16 h. MeOH (50 mL)was added and the reaction mixture was stirred for 60 h. The pH wasadjusted to 7 with 1 M aq HCl solution and the solvents were removed invacuo. The residue was stirred in MeOH (50 mL) and the resulting whiteprecipitate was removed by filtration. The solvents were removed invacuo to give a crude orange gum (17.0 g). 11.0 g of this residue wasstirred in hot EtOH/EtOAc, cooled and the resulting precipitate wasremoved by filtration. The solvents were removed in vacuo and theresidue was purified by recrystallisation from hot MeOH/Et₂O to give(4S,6S)-5-[(benzyloxy)carbonyl]-4-isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylicacid (2.50 g, 13.8%) as a white solid.

Analytical LCMS: purity >95% (System A, R_(T)=1.53 min), ES⁺: 344.6[MH]⁺.

Example 1 2,2,2-Trichloroethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

Intermediate 1 (2.33 g, 3.50 mmol, 45% pure) was suspended in DCM (20mL) and DIPEA (1.83 mL, 10.5 mmol) and 2,2,2-trichloroethylchloroformate (1.06 mL, 7.70 mmol) were added. The reaction mixture wasstirred at room temperature for 16 h. The reaction mixture waspartitioned between DCM (30 mL) and sat aq NaHCO₃ solution (20 mL). Theorganic layer was washed with sat aq NaHCO₃ solution (2×20 mL) and water(20 mL) and concentrated in vacuo. The residue was dissolved in MeOH (20mL) and 1M aq NaOH solution (10 mL) was added. The reaction mixture wasstirred for 1 h and the pH was adjusted to 7 with 1 M aq HCl solutionand the solvents were removed in vacuo. The residue was partitionedbetween DCM (20 mL) and water (20 mL) and the organic layer was washedwith water (20 mL), dried (MgSO₄) and concentrated in vacuo. The residuewas purified by reverse phase HPLC (YMC ODS-A 100×20 mm, 5 μm, 25mL/min, gradient 50% to 70% (over 7 min) then 100% (3 min) MeOH in 10%MeOH/water) to give 2,2,2-trichloroethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(97 mg, 8%) as a white solid.

Analytical HPLC: purity 99.6% (System B, R_(T)=4.88 min); AnalyticalLCMS: purity 99.8% (System B, R_(T)=5.23 min), ES⁺: 342.3 [MH]⁺; HRMScalculated for C₁₂H₁₆Cl₃N₃O₂: 339.0308. found 339.0311.

Example 2 2-Chloro-2,2-difluoroethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

2-Chloro-2,2-difluoroethanol (1.69 g, 14.5 mmol) was dissolved in DCM(10 mL) at 0° C. and NMM (1.40 mL, 14.5 mmol) and 4-nitrophenylchloroformate (2.93 g, 14.5 mmol) were added. The reaction mixture wasstirred at room temperature for 5 h. A solution of Intermediate 1 (1.87g, 2.97 mmol, 32% pure) and DIPEA (2.52 mL, 14.5 mmol) in DCM (20 mL)was added and the resulting solution was stirred for 2 d. The solventswere removed in vacuo, the residue was dissolved in MeOH (8 mL) and 1 Maq NaOH solution (6 mL) and the reaction mixture was stirred at roomtemperature for 18 h and concentrated in vacuo. The residue wasdissolved in EtOAc (100 mL) and the organic layer was washed with 1M aqNa₂CO₃ solution (6×100 mL), dried (MgSO₄) and concentrated in vacuo. Theresidue was purified by column chromatography (normal phase, 20 g,Strata SI-1, silica gigatube, DCM (200 mL) followed by 2% and 4% MeOH inDCM (200 mL each)) and by reverse phase HPLC (YMC ODS-A 150×20 mm, 5 μm,15 mL/min, isocratic run at 55% (over 12 min) then 100% (3 min) MeOH in10% MeOH/water) to give 2-chloro-2,2-difluoroethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo-[4,5-c]pyridine-5-carboxylate(13.0 mg, 1.4%) as a white solid.

Analytical HPLC: purity 99.0% (System B, R_(T)=4.47 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.95 min), ES⁺: 308.0 [³⁵ClMH]⁺ and310.0 [³⁷ClMH]⁺; HRMS calculated for C₁₂H₁₆ClF₂N₃O₂: 307.0899. found307.0898.

Example 3 Benzyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

Benzyl alcohol (0.88 g, 8.10 mmol) was dissolved in DCM (10 mL) and thereaction mixture was cooled to 0° C. NMM (0.89 mL, 8.10 mmol) and4-nitrophenyl chloroformate (1.63 g, 8.10 mmol) were added and thereaction mixture was stirred at room temperature for 5 h. A solution ofIntermediate 1 (1.16 g, 3.17 mmol, 55% pure) and DIPEA (2.69 mL, 15.4mmol) in DCM (20 mL) was added and the resulting solution was stirredfor 18 h. The solvents were removed in vacuo, the residue was dissolvedin MeOH (10 mL) and 1 M aq NaOH solution (10 mL) and the reactionmixture was stirred for 2 h. The solvents were removed in vacuo, theresidue was dissolved in EtOAc (120 mL), the organic layer was washedwith 1 M aq Na₂CO₃ solution (4×100 mL), dried (MgSO₄) and the solventswere removed in vacuo. The residue was purified by column chromatography(normal phase, 20 g, Strata SI-1, silica gigatube, 0% to 5% MeOH inDCM), and by reverse phase HPLC (YMC ODS-A 100×20 mm, 5 μm, 25 mL/min,gradient 40% to 100% (over 7 min) then 100% (3 min) MeOH in 10%MeOH/water and YMC ODS-A 100×20 mm, 5 μm, 25 mL/min, gradient 0% to 100%(over 7 min) then 100% (3 min) MeOH in 10% MeOH/water to give benzyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(65.8 mg, 6.9%) as a white solid.

Analytical HPLC: purity 100% (System B, R_(T)=4.74 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.99 min), ES⁺: 300.0 [MH]⁺; HRMScalculated for C₁₇H₂₁N₃O₂: 299.1634. found 299.1636.

Example 4 3-Chlorobenzyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

Carbonic acid 3-chloro-benzyl ester 4-nitro-phenyl ester (1.34 g, 4.40mmol) was dissolved in DCM (10 mL) and cooled to 0° C. A solution ofIntermediate 1 (1.00 g, 1.79 mmol, 36% pure) and DIPEA (0.70 mL, 6.60mmol) in DCM (10 mL) was added and the reaction mixture was stirred atroom temperature for 16 h. The solvent was removed in vacuo and theresidue was dissolved in MeOH (8 mL) and 1M aq NaOH solution (6 mL) andstirred at room temperature for 2 h. The solvents were removed in vacuoand the residue was dissolved in EtOAc. The organic layer was washedwith 1M aq Na₂CO₃ solution (8×50 mL), dried (MgSO₄) and concentrated invacuo. The residue was purified by reverse phase HPLC (YMC ODS-A 100×20mm, 5 μm, 25 mL/min, gradient 40% to 100% (over 7 min) then 100% (3 min)MeOH in 10% MeOH/water) to give 3-chlorobenzyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(116 mg, 19.5%) as a colourless gum.

Analytical HPLC: purity 98.8% (System B, R_(T)=5.06 min); AnalyticalLCMS: purity 100% (System B, R_(T)=5.47 min), ES⁺: 334.0 [MH]⁺; HRMScalculated for C₁₇H₂₀ClN₃O₂: 333.1244. found 333.1252.

Example 5 4-Chlorobenzyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

(4-Chloro-phenyl)-methanol (0.51 g, 3.60 mmol) was suspended in DCM (10mL) and NMM (0.35 mL, 3.60 mmol) and 4-nitrophenyl chloroformate (0.73g, 3.6 mmol) were added at 0° C. The reaction was stirred at roomtemperature for 16 h. A solution of Intermediate 1 (500 mg, 1.49 mmol,60% pure) and DIPEA (940 μL, 5.40 mmol) in DCM (10 mL) was added and theresulting solution was stirred at room temperature for 15 h. Thesolvents were removed in vacuo. The residue was dissolved in MeOH (8 mL)and 1 M aq NaOH solution (6 mL) and the reaction mixture was stirred for2 h and concentrated in vacuo. The residue was dissolved in EtOAc (100mL) and the organic layer washed with 1 M aq Na₂CO₃ solution (6×50 mL),brine (2×50 mL), dried (MgSO₄) and the solvents removed in vacuo. Theresidue was purified by reverse phase HPLC (YMC ODS-A 100×20 mm, 5 μm,25 mL/min, gradient 50% to 80% (over 7 min) then 100% (3 min) MeOH in10% MeOH/water) to give 4-chlorobenzyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(29.5 mg, 5.9%) as a colourless gum.

Analytical HPLC: purity 98.6% (System B, R_(T)=5.14 min); AnalyticalLCMS: purity 100% (System B, R_(T)=5.49 min), ES⁺: 334.0 [MH]⁺; HRMScalculated for C₁₇H₂₀ClN₃O₂: 333.1244. found 333.1237.

Example 6 Pyridin-2-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

NaH (0.22 g, 5.0 mmol, 60% dispersion in mineral oil) was suspended inanhydrous THF (15 mL), the suspension was cooled to 0° C. and2-pyridylmethanol (0.55 g, 5.0 mmol) was added. The suspension wasstirred at 0° C. for 1 h and added to a stirred solution of Intermediate2 (0.66 g, 2.00 mmol, 70% pure) in THF (10 mL) and the reaction mixturewas stirred at room temperature. Two additional such portions of NaH and2-pyridylmethanol in THF were added after 18 and 36 h, respectively.After 54 h the reaction mixture was quenched with water (10 mL), thesolvents were removed in vacuo and the residue was dissolved in EtOAc(100 mL), washed with 1 M aq Na₂CO₃ solution (4×100 mL), dried (MgSO₄)and the solvents were removed in vacuo. The residue was purified bycolumn chromatography (normal phase, 20 g, Strata SI-1, silica gigatube,DCM (200 mL) followed by 1%, 2% and 5% MeOH in DCM (200 mL each)) andreverse phase HPLC (Phenomenex Synergi, RP-Hydro 150×10 mm, 10 μm, 15mL/min, gradient 0% to 70% (over 12 min) to 100% (over 3 min) MeOH inwater (1% formic acid)). The residue was de-salted using K₂CO₃ in DCM togive pyridin-2-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(86.4 mg, 14.4%) as a white solid.

Analytical HPLC: purity 100% (System B, R_(T)=3.16 min); AnalyticalLCMS: purity 97.9% (System B, R_(T)=3.55 min), ES⁺: 301.1 [MH]⁺; HRMScalculated for C₁₆H₂₀N₄O₂: 300.1586. found 300.1581.

Example 7 Pyridin-3-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

NaH (0.19 g, 4.80 mmol, 60% dispersion in mineral oil) was suspended inanhydrous THF (5 mL), the suspension cooled to 0° C. and3-pyridylcarbinol (0.40 mL, 4.00 mmol) was added. The suspension wasstirred at 0° C. for 30 min and then added to a solution of Intermediate2 (1.33 g, 4.00 mmol, 70% pure) in THF (10 mL) and the reaction mixturewas stirred at room temperature. Two additional such portions of NaH and3-pyridylcarbinol in THF were added after 7 and 25 h, respectively.After 4 d the reaction mixture was quenched with water (10 mL) and thesolvents were removed in vacuo. The residue was dissolved in EtOAc (100mL) washed with 1 M aq Na₂CO₃ solution (4×100 mL), dried (MgSO₄) and thesolvents were removed in vacuo. The residue was purified by columnchromatography (normal phase, 20 g, Strata SI-1, silica gigatube, DCM(200 mL) followed by 2%, 4%, 5% and 10% MeOH in DCM (200 mL each)) andreverse phase HPLC (Phenomenex Synergi, RP-Hydro 150×10 mm, 10 μm, 15mL/min, gradient 0% to 80% (over 12 min) to 100% (over 3 min) MeOH inwater (1% formic acid) and Phenomenex Synergi, RP-Hydro 150×10 mm, 10μm, 15 mL/min, gradient 0% to 40% (over 12 min) to 100% (over 3 min)MeOH in water (1% formic acid)). The residue was de-salted using K₂CO₃in DCM to give pyridin-3-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(46.3 mg, 3.8%) as a white solid.

Analytical HPLC: purity 100% (System B, R_(T)=3.07 min); AnalyticalLCMS: purity 99% (System B, R_(T)=3.07 min), ES⁺: 301.6; HRMS calculatedfor C₁₆H₂₀N₄O₂: 300.1586. found 300.1579.

Example 8 Pyridin-4-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

Intermediate 1 (476 mg, 1.65 mmol, 70% pure) and DIPEA (1.39 mL, 8.00mmol) were dissolved in DMF (20 mL) and carbonic acid 4-nitro-phenylester pyridin-4-ylmethyl ester (1.10 g, 4.00 mmol) was added. Thereaction mixture was stirred at room temperature for 20 h and thesolvents were removed in vacuo. The residue was dissolved in MeOH (10mL) and 1 M aq NaOH solution (3 mL) was added. The reaction mixture wasstirred at room temperature for 1 h and the solvents were removed invacuo. The residue was dissolved in DCM (40 mL) and washed with 1 M aqNa₂CO₃ solution (5×40 mL). The organic layer was dried (MgSO₄) and thesolvents were removed in vacuo. The residue was purified by reversephase column chromatography (LiChroprep RP-18, 40-63 μm, 460×26 mm (100g), 30 mL per min, gradient 0% to 100% (over 35 min) MeOH in water andLiChroprep RP-18, 40-63 μm, 460×26 mm (100 g), 30 mL per min, gradient50% to 100% (over 35 min) MeOH in water) and reverse phase HPLC (YMCODS-A 150×20 mm, 5 μm, 15 mL/min, gradient 0% to 50% (over 12 min) then100% (3 min) MeOH in 10% MeOH/water) to give pyridin-4-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(82 mg, 16.5%) as a white solid.

Analytical HPLC: purity 100% (System B, R_(T)=3.05 min); AnalyticalLCMS: purity 100% (System B, R_(T)=3.42 min), ES⁺: 301.1 [MH]⁺; HRMScalculated for C₁₆H₂₀N₄O₂: 300.1586. found 300.1568.

Example 9 (5-Chloropyridin-2-yl)methyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

5-Chloropyridine-2-carboxylic acid (2.00 g, 12.7 mmol) was dissolved inTHF (12 mL) at 0° C. and added to a solution of borane-THF (19.0 mL, 1 Min THF, 19.0 mmol). THF (10 mL) was added and the reaction mixture waswarmed to room temperature, stirred for 2 h and heated under reflux at70° C. for 3 h. The reaction mixture was cooled to 0° C., quenched withaq 6 M HCl solution (4 mL) and the solution was stirred for 2 h andconcentrated in vacuo. The residue was partitioned between H₂O (75 mL)and DCM (75 mL). The aq layer was washed with DCM (3×75 mL), adjusted topH 9 with 4 M aq NaOH (3 mL) and extracted with DCM (3×75 mL). Theorganic layers were combined, dried (MgSO₄) and concentrated in vacuo togive 5-chloropyridine-2-methanol (0.83 g, 45%) as a brown gum.

Analytical HPLC: purity 79.5% (System B, R_(T)=3.04 min); AnalyticalLCMS: purity 85% (System A, R_(T)=1.15 min), ES⁺: 143.97 [³⁵ClMH]⁺ and145.98 [MH ³⁷Cl]⁺.

NaH (80.0 mg, 2.00 mmol, 60% dispersion in mineral oil) was suspended inTHF (10 mL), the suspension was cooled to 0° C. and5-chloropyridine-2-methanol (0.29 g, 2.00 mmol) was added. Thesuspension was stirred at 0° C. for 30 min then added to a solution ofIntermediate 2 (0.65 g, 2.00 mmol, 70% pure) in THF (10 mL) and thereaction mixture was stirred at room temperature. Two additional suchportions of NaH and 5-chloropyridine-2-methanol in THF were added after2 and 3 d, respectively. After 4 d the reaction mixture was quenchedwith water (10 mL) and the solvents were removed in vacuo. The solventswere removed in vacuo and the residue was dissolved in EtOAc (100 mL)washed with 1 M aq Na₂CO₃ solution (4×100 mL), dried (MgSO₄) and thesolvents were removed in vacuo. The residue was purified by columnchromatography (normal phase, 20 g, Strata SI-1, silica gigatube, DCM(200 mL) followed by 2%, 4%, 5% and 10% MeOH in DCM (200 mL each)) andreverse phase HPLC (Phenomenex Synergi, RP-Hydro 150×10 mm, 10 μm, 15mL/min, gradient 20% to 80% (over 12 min) to 100% (over 3 min) MeOH inwater (1% formic acid)). The residue was de-salted using K₂CO₃ to give(5-chloropyridin-2-yl)methyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(7.91 mg, 1.2%) as a white solid.

Analytical HPLC: purity 99.2% (System B, R_(T)=4.40 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.25 min), ES⁺: 335.10 [³⁵ClMH]⁺ and337.10 [MH ³⁷Cl]⁺; HRMS calculated for C₁₆H₁₉ClN₄O₂: 334.1197. found334.1189.

Example 10 Pyrazin-2-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

NaH (0.22 g, 5.60 mmol, 60% dispersion in mineral oil) was suspended inTHF (10 mL), cooled to 0° C. and pyrazin-2-yl methanol (0.49 mL, 5.00mmol) was added. The suspension was stirred at 0° C. for 30 min and thenadded to a solution of Intermediate 2 (0.66 g, 2.00 mmol, 70% pure) inTHF (10 mL) and the reaction mixture was stirred at room temperature. Anadditional such portion of NaH and pyrazin-2-yl methanol in THF wasadded after 18 h. After 2 d the reaction mixture was quenched with water(10 mL) and the solvents were removed in vacuo. The residue wasdissolved in MeOH (10 mL) and 1 M aq NaOH solution (10 mL) and thereaction mixture was stirred at room temperature for 2 h thenconcentrated in vacuo. The residue was dissolved in EtOAc (120 mL) andthe organic layer was washed with 1 M aq Na₂CO₃ solution (6×100 mL),dried (MgSO₄) and the solvents were removed in vacuo. The residue waspurified by reverse phase HPLC (Phenomenex Synergi, RP-Hydro 150×10 mm,10 μm, 15 mL/min, gradient 0% to 100% (over 12 min) then 100% (over 3min) MeOH in water (1% formic acid)). The residue was de-salted usingK₂CO₃ in DCM to give pyrazin-2-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(62.9 mg, 10.4%) as a white solid.

Analytical HPLC: purity 99.2% (System B, R_(T)=3.59 min); AnalyticalLCMS: purity 100% (System B, R_(T)=3.99 min), ES⁺: 302.1 [MH]⁺; HRMScalculated for C₁₅H₁₉N₅O₂: 301.1539. found 301.1527.

Example 11 Benzyl(4S,6S)-6-(aminocarbonyl)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]-pyridine-5-carboxylate

Intermediate 4 (572 mg, 1.67 mmol) and ammonium chloride (178 mg, 3.33mmol) were dissolved in DMF (5 mL), and DIPEA (1.16 mL, 6.66 mmol), HOBt(338 mg, 2.50 mmol) and HBTU (948 mg, 2.50 mmol) were added. Thereaction mixture was stirred at room temperature for 3 d andconcentrated in vacuo. The residue was partitioned between EtOAc (100mL) and sat aq NaHCO₃ solution (80 mL). The organic layer was washedwith sat aq NaHCO₃ solution (80 mL), dried (MgSO₄) and concentrated invacuo. The residue was purified by column chromatography (normal phase,20 g, Strata SI-1, silica gigatube, DCM (200 mL) followed by 2%, 4%, 5%and 10% MeOH in DCM (200 mL each) and reverse phase HPLC (YMC ODS-A100×20 mm, 5 μm, 25 mL/min, gradient 40% to 70% (over 7 min) then 100%(3 min) MeOH in 10% MeOH/water) to give benzyl(4S,6S)-6-(aminocarbonyl)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(163 mg, 28.7%) as a white solid.

Analytical HPLC: purity 99.4% (System B, R_(T)=4.20 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.13 min), ES⁺: 343.7 [MH]⁺; HRMScalcd for C₁₈H₂₂N₄O₃: 342.1692. found 342.1683.

Example 12 Benzyl(4S,6S)-4-isopropyl-6-[(methylamino)carbonyl]-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

Intermediate 4 (200 mg, 0.58 mmol) was dissolved in DMF (3 mL) and NMM(160 μL, 1.46 mmol), EDC. HCl (246 mg, 1.28 mmol), HOBt (197 mg, 1.46mmol) and methylamine (0.87 mL, 2 M in THF, 1.75 mmol) were added. Thereaction mixture was stirred at room temperature for 3 d. The solventswere removed in vacuo. The residue was partitioned between EtOAc (50 mL)and sat aq NaHCO₃ solution (50 mL). The organic layer was washed withsat aq NaHCO₃ solution (2×50 mL), dried (MgSO₄) and the solvents wereremoved in vacuo. The residue was purified by reverse phase HPLC (YMCODS-A 100×20 mm, 5 μm, 25 mL/min, gradient 30% to 90% (over 7 min) then100% (3 min) MeOH in 10% MeOH/water) and reverse phase HPLC (YMC ODS-A100×20 mm, 5 μm, 25 mL/min, gradient 40% to 80% (over 7 min) then 100%(3 min) MeOH in 10% MeOH/water) to give benzyl(4S,6S)-4-isopropyl-6-[(methylamino)carbonyl]-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(5 mg, 2.41%) as a white solid.

Analytical HPLC: purity 98.4% (System B, R_(T)=4.40 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.37 min), ES⁺: 357.7 [MH]⁺; HRMScalcd for C₁₉H₂₄N₄O₃: 356.1848. found 356.1843.

Example 13 5-Benzyl6-methyl(4S,6S)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5,6-dicarboxylate

Intermediate 3 (1.00 g, 4.80 mmol) was dissolved in MeOH (10 mL) andconc. HCl (10 mL) was added. The reaction mixture was heated at 85° C.for 4 h. The solvents were removed in vacuo to give methyl(6S)-4-isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylatedihydrochloride (mixture of 4S and 4R diastereomers; 1.42 g, crude,100%). Analytical LCMS: purity 88% (System A, R_(T)=0.51 min), ES⁺:224.54 [MH]⁺.

Methyl(6S)-4-isopropyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylatedihydrochloride (mixture of 4S and 4R diastereomers; 1.42 g, 4.80 mmol)and DIPEA (4.18 mL, 24.0 mmol) were dissolved in THF (20 mL), thereaction mixture was cooled to 0° C. and benzyl chloroformate (1.37 mL,9.60 mmol) was added. The reaction mixture was warmed to roomtemperature over 16 h. The reaction mixture was filtered and thefiltrate was concentrated in vacuo to give a 2:1 mixture of 3,5-dibenzyl6-methyl(6S)-4-isopropyl-6,7-dihydro-3H-imidazo[4,5-c]pyridine-3,5,6(4H)-tricarboxylateand 5-benzyl6-methyl(6S)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5,6-dicarboxylate(mixture of 4S and 4R diastereomers; 3.05 g, crude).

Analytical LCMS: purity 23% (System A, R_(T)=1.65 min), ES⁺: 358.5 and66% (R_(T)=2.24 min), ES⁺: 492.6.

A 2:1 mixture of 3,5-dibenzyl6-methyl(6S)-4-isopropyl-6,7-dihydro-3H-imidazo[4,5-c]-pyridine-3,5,6(4H)-tricarboxylateand 5-benzyl6-methyl(6S)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5,6-dicarboxylate(mixture of 4S and 4R diastereomers; 600 mg, ˜1.20 mmol) was dissolvedin DMF (6 mL) and methylamine (1.22 mL, 2 M in THF, 2.44 mmol) wasadded. The reaction mixture was split into 3 equal portions. The firstreaction mixture was stirred at room temperature for 18 h. The secondreaction mixture was heated at 60° C. for 4 h, methylamine (0.20 mL, 2 Min THF, 0.41 mmol) was added and the reaction mixture was heated underreflux at 80° C. for 18 h. The third reaction mixture was heated using aBiotage microwave (100° C., absorption high, pre-stirring 20 sec) for 20min, methylamine (0.20 mL, 2 M in THF, 0.41 mmol) was added and thereaction mixture was heated using a Biotage microwave (120° C.,absorption high, pre-stirring 20 sec) for 20 min. Methylamine (1.00 mL,2 M in THF, 2.00 mmol) was added and the reaction mixture was heatedusing a Biotage microwave (160° C., absorption high, pre-stirring 20sec) for 20 min. The 3 reaction mixtures were combined and the solventswere removed in vacuo. The residue was partitioned between EtOAc (30 mL)and sat aq NaHCO₃ solution (30 mL). The organic layer was washed withsat aq NaHCO₃ solution (30 mL), brine (30 mL), dried (MgSO₄) and thesolvents were removed in vacuo. The residue was purified by columnchromatography (normal phase, 20 g, Strata SI-1, silica gigatube, DCM(200 mL) followed by 2%, 4% and 5% MeOH in DCM (200 mL each)) and byreverse phase HPLC (YMC ODS-A 100×20 mm, 5 μm, 25 mL/min, gradient 40%to 90% (over 7 min) then 100% (3 min) MeOH in 10% MeOH/water) to give5-benzyl6-methyl(4S,6S)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5,6-dicarboxylate(46.2 mg, 2.7%) as a white solid.

Analytical HPLC: purity 99.7% (System B, R_(T)=4.93 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.86 min), ES⁺: 358.6 [MH]⁺; HRMScalculated for C₁₉H₂₃N₃O₄: 357.1689. found 357.1687.

Example 14 2-Phenoxyethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

2-Phenoxy-ethanol (500 mg, 3.60 mmol) and NMM (0.36 g, 0.35 mL, 3.60mmol) were suspended in DCM (10 mL), cooled to 0° C. and 4-nitrophenylchloroformate (0.72 g, 3.60 mmol) was added. The reaction mixture wasstirred at room temperature for 2 h. A solution of Intermediate 1 (900mg, 1.47 mol, 33% pure) and DIPEA (940 μL, 5.40 mmol) in DCM (20 mL) wasadded and the resulting solution was stirred at room temperature for 15h, washed with 1 M aq Na₂CO₃ solution (6×100 mL), dried (MgSO₄) and thesolvents were removed in vacuo. The residue was dissolved in MeOH (8 mL)and 1M aq NaOH solution (6 mL) and the reaction mixture was stirred atroom temperature for 2 h then concentrated in vacuo. The residue wasdissolved in EtOAc (100 mL) and the organic layer was washed with 1 M aqNa₂CO₃ solution (2×100 mL), brine (2×100 mL), dried (MgSO₄) and thesolvents removed in vacuo. The residue was purified by reverse phaseHPLC (YMC ODS-A 100×20 mm, 5 μm, 25 mL/min, gradient 30% to 50% (over 7min) then 100% (3 min) MeOH in 10% MeOH/water) and reverse phase HPLC(YMC ODS-A 100×20 mm, 5 μm, 25 mL/min, gradient 50% to 70% (over 7 min)then 100% (3 min) MeOH in 10% MeOH/water) to give 2-phenoxyethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(27.2 mg, 5.6%) as a white gum.

Analytical HPLC: purity 100% (System B, R_(T)=4.79 min); AnalyticalLCMS: purity 100% (System B, R_(T)=5.17 min), ES⁺: 330.1 [MH]⁺; HRMScalculated for C₁₈H₂₃N₃O₃: 329.1739. found 329.1729.

Example 15 2-(4-Chlorophenoxyl)ethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

2-(p-Chlorophenoxy)ethanol (0.73 g, 4.20 mmol) and NMM (0.55 mL, 5.70mmol) were dissolved in DCM (10 mL), cooled to 0° C. and 4-nitrophenylchloroformate (1.15 g, 5.70 mmol) was added. The reaction mixture wasstirred at room temperature for 5 h. A solution of Intermediate 1 (0.70g, 1.74 mmol, 50% pure) and DIPEA (1.48 mL, 8.50 mmol) in DCM (20 mL)was added and the resulting solution was stirred at room temperature for2 d. The solvents were removed in vacuo, the residue was dissolved inMeOH (8 mL) and 1 M aq NaOH solution (6 mL) and the reaction mixture wasstirred at room temperature for 3 h then concentrated in vacuo. Theresidue was dissolved in EtOAc (100 mL), washed with 1 M aq Na₂CO₃solution (6×100 mL), dried (MgSO₄) and the solvents were removed invacuo. The residue was purified reverse phase HPLC (YMC ODS-A 100×20 mm,5 μm, 25 mL/min, gradient 70 to 100% (over 7 min) then 100% (3 min) MeOHin 10% MeOH/water) to give 2-(4-chlorophenoxyl)ethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(40.0 mg, 6.3%) as a white solid.

Analytical HPLC: purity 99.7% (System B, R_(T)=5.21 min); AnalyticalLCMS: purity 100% (System B, R_(T)=5.54 min), ES⁺: 364.0 [MH ³⁵Cl]⁺ and366.0 [MH ³⁷Cl]⁺; HRMS calculated for C₁₈H₂₂ClN₃O₃: 363.1350. found363.1350.

Example 16(3S)-Tetrahydrofuran-3-yl(4S)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]-pyridine-5-carboxylate

NaH (0.40 g, 10.0 mmol, 60% dispersion in mineral oil) was suspended inanhydrous THF (20 mL), cooled to 0° C. and (S)-3-hydroxytetrahydrofuran(0.88 g, 0.68 mL, 10.0 mmol) was added. The suspension was stirred at 0°C. for 30 min then added to a solution of Intermediate 2 (3.30 g, 10.0mmol, 70% pure) in THF (60 mL) and the reaction mixture was stirred atroom temperature. Two additional such portions of NaH and(S)-3-hydroxytetrahydrofuran in THF were added after 5 and 29 h,respectively. After 2 d the reaction mixture was quenched with water (10mL) and the solvents were removed in vacuo. The residue was dissolved inEtOAc (100 mL), washed with 1 M aq Na₂CO₃ solution (4×100 mL), dried(MgSO₄) and the solvents were removed in vacuo. The residue was purifiedby column chromatography (normal phase, 20 g, Strata SI-1, silicagigatube, DCM (200 mL) followed by 2%, 4% and 5% MeOH in DCM (200 mLeach)) and reverse phase HPLC (YMC ODS-A 100×20 mm, 5 μm, 25 mL/min,gradient 30% to 60% (over 7 min) then 100% (3 min) MeOH in 10%MeOH/water) to give (3S)-tetrahydrofuran-3-yl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(34.8 mg, 1.1%) as a white solid.

Analytical HPLC: purity 100% (System B, R_(T)=3.63 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.01 min), ES⁺: 280.1 [MH]⁺.

(3S)-Tetrahydrofuran-3-yl-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(39.91 mg) was dissolved in 10 mM ammonium formate buffer and MeOH (2mL, 1:1) and purified twice by reverse phase chiral HPLC (Chirobiotic T250×10 mm, 3 mL/min, isocratic run 70% MeOH in 10 mM ammonium formatebuffer (40 min), pH 7.4) to give a single diastereoisomer assigned as(3S)-tetrahydrofuran-3-yl(4S)-4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(6.90 mg, 99% ee).

Analytical HPLC: purity 100% (System B, R_(T)=3.63 min); Chiral HPLC:purity 99.5% (System C, R_(T)=2.22 min); Analytical LCMS: purity 100%(System B, R_(T)=3.90 min), ES⁺: 280.1 [MH]⁺; HRMS calculated forC₁₄H₂₁N₃O₃: 279.1583. found 279.1571.

Example 17 Tetrahydrofuran-3-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

Tetrahydro-3-furan-methanol (0.61 mL, 6.40 mmol) and NMM (0.64 g, 0.70mL, 6.40 mmol) were dissolved in DCM (10 mL) at 0° C. and 4-nitrophenylchloroformate (1.28 g, 6.40 mmol) was added. The reaction mixture wasstirred at room temperature for 5 h. A solution of Intermediate 1 (0.50g, 2.48 mmol) in DCM (20 mL) and DIPEA (2.11 mL, 12.1 mmol) was added tothe reaction mixture and the resulting solution was stirred at roomtemperature for 18 h. The solvents were removed in vacuo, the residuewas dissolved in MeOH (10 mL) and 1 M aq NaOH solution (10 mL) and thereaction mixture was stirred at room temperature for 2 h andconcentrated in vacuo. The residue was dissolved in EtOAc (120 mL) andthe organic layer was washed with 1 M aq Na₂CO₃ solution (4×100 mL),dried (MgSO₄) and the solvents were removed in vacuo. The residue waspurified by column chromatography (normal phase, 20 g, Strata SI-1,silica gigatube, DCM (200 mL)) followed by 2%, 4%, 5% and 10% MeOH inDCM (200 mL each)) and reverse phase HPLC (YMC ODS-A 100×20 mm, 5 μm, 25mL/min, gradient 20% to 100% (over 7 min) then 100% (3 min) MeOH in 10%MeOH/water and YMC ODS-A 100×20 mm, 5 μm, 25 mL/min, gradient 20% to 80%(over 7 min) then 100% (3 min) MeOH in 10% MeOH/water) to givetetrahydrofuran-3-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(37.8 mg, 5.2%) as a white solid.

Analytical HPLC: purity 100% (System B, R_(T)=3.83 min); AnalyticalLCMS: purity 100% (System B, R_(T)=3.89 min), ES⁺: 294.7 [MH]⁺; HRMScalculated for C₁₅H₂₃N₃O₃: 293.1739. found 293.1744.

Example 18 (3-Methyloxetan-3-yl)methyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

NaH (0.19 g, 4.80 mmol, 60% dispersion in mineral oil) was suspended inanhydrous THF (10 mL), cooled to 0° C. and 3-methyl-3-oxetane methanol(0.41 g, 4.00 mmol) was added. The suspension was stirred at 0° C. for30 min then added to a solution of Intermediate 2 (1.33 g, 4.00 mmol,70% pure) in THF (10 mL) and the reaction mixture was stirred at roomtemperature. Two additional such portions of NaH and 3-methyl-3-oxetanemethanol in THF were added after 8 and 32 h, respectively. After 50 hthe reaction mixture was quenched with water (10 mL) and the solventswere removed in vacuo. The residue was dissolved in EtOAc (100 mL)washed with 1 M aq Na₂CO₃ solution (4×100 mL), dried (MgSO₄) and thesolvents were removed in vacuo. The residue was purified by columnchromatography (normal phase, 20 g, Strata SI-1, silica gigatube, DCM(200 mL) followed by 2%, 4%, 5%, 10% and 20% MeOH in DCM (200 mL each))and by reverse phase HPLC (YMC ODS-A 100×20 mm, 5 μm, 25 mL/min,gradient 20% to 100% (over 7 min) then 100% (3 min) MeOH in 10%MeOH/water) to give (3-methyloxetan-3-yl)methyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(68.2 mg, 5.8%) as a white solid.

Analytical HPLC: purity 100% (System B, R_(T)=3.80 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.08 min), ES⁺: 294.1 [MH]⁺; HRMScalculated for C₁₅H₂₃N₃O₃: 293.1739. found 293.1740.

Example 19 2-(Dimethylamino)ethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

N,N-Dimethylethanolamine (1.46 mL, 14.5 mmol) was dissolved in DCM (10mL) at 0° C. and NMM (1.40 mL, 14.5 mmol) and 4-nitrophenylchloroformate (2.93 g, 13.5 mmol) were added. The reaction mixture wasstirred at room temperature for 5 h. A solution of Intermediate 1 (2.36g, 3.6 mmol) and DIPEA (2.53 mL, 14.5 mmol) in DCM (20 mL) was added andthe resulting solution was stirred for 2 d. The solvents were removed invacuo, the residue was dissolved in MeOH (8 mL) and 1 M aq NaOH solution(6 mL) and the reaction mixture was stirred for 18 h and concentrated invacuo. The residue was dissolved in EtOAc (100 mL) and the organic layerwas washed with 1 M aq Na₂CO₃ solution (6×100 mL), dried (MgSO₄) andconcentrated in vacuo. The residue was purified by column chromatography(normal phase, 20 g, Strata SI-1, silica gigatube, DCM (200 mL) followedby 2% and 4% MeOH in DCM (200 mL each)) and reverse phase HPLC (YMCODS-A 100×20 mm, 5 μm, 25 mL per min, gradient 40% to 80% (over 7 min)then 100% (3 min) MeOH in 10% MeOH/water) to give 2-(dimethylamino)ethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(7 mg, 0.7%) as a colourless gum.

Analytical HPLC: purity 98.6% (System B, R_(T)=2.90 min); AnalyticalLCMS: purity 100% (System B, R_(T)=2.81 min), ES⁺: 281.8 [MH]⁺; HRMScalculated for C₁₄H₂₄N₄O₂: 280.1899. found 280.1905.

Example 20 (2R)-Tetrahydrofuran-2-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]-pyridine-5-carboxylate

(R)-tetrahydrofurfuryl alcohol (1.00 g, 9.80 mmol) was dissolved in DCM(10 mL) at 0° C. and NMM (0.99 g, 0.94 mL, 9.80 mmol) and 4-nitrophenylchloroformate (1.97 g, 9.80 mmol) were added. The reaction mixture wasstirred at room temperature for 5 h. A solution of Intermediate 1 (1.87g, 3.6 mmol) and DIPEA (2.53 mL, 14.5 mmol) in DCM (20 mL) was added andthe resulting solution was stirred for 2 d. The solvents were removed invacuo, and the residue was dissolved in MeOH (8 mL) and 1 M aq NaOHsolution (6 mL) and the reaction mixture was stirred for 18 h andconcentrated in vacuo. The residue was dissolved in EtOAc (100 mL) andthe organic layer was washed with 1 M aq Na₂CO₃ solution (6×100 mL),dried (MgSO₄) and concentrated in vacuo. The residue was purified byreverse phase column chromatography (LiChroprep RP-18, 40-63 μm, 460×26mm (100 g), 30 mL per min, gradient 0% to 20% (over 5 min) to 90% (over40 min) MeOH in water) and reverse phase HPLC (YMC ODS-A 150×20 mm, 5μm, 15 mL per min, gradient 50% to 65% (over 12 min) then 100% (3 min)MeOH in 10% MeOH/water) to give (2R)-tetrahydrofuran-2-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(46.7 mg, 4.4%) as a colourless gum.

Analytical HPLC: purity 99.4% (System B, R_(T)=3.75 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.29 min), ES⁺: 294.1 [MH]⁺; HRMScalculated for C₁₅H₂₃N₃O₃: 293.1739. found 293.1738.

Example 21 1,3-Thiazol-2-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

2-Hydroxymethylthiazole (0.97 g, 8.40 mmol) was dissolved in DCM (10 mL)at 0° C. and NMM (0.85 g, 0.81 mL, 8.40 mmol) and 4-nitrophenylchloroformate (1.70 g, 8.40 mmol) were added. The reaction mixture wasstirred at room temperature for 5 h. A solution of Intermediate 1 (2.18g, 4.20 mmol) and DIPEA (1.64 g, 2.21 mL, 12.7 mmol) in DCM (20 mL) wasadded and the resulting solution was stirred for 19 h. The solvents wereremoved in vacuo, the residue was dissolved in MeOH (8 mL) and 1 M aqNaOH solution (6 mL) and the reaction mixture was stirred at roomtemperature for 3 d and concentrated in vacuo. The residue was dissolvedin EtOAc (100 mL) and the organic layer was washed with 1 M aq Na₂CO₃solution (6×100 mL), dried (MgSO₄) and concentrated in vacuo. Theresidue was purified by column chromatography (normal phase, 20 g,Strata SI-1, silica gigatube, DCM (200 mL) followed by 2% and 4% MeOH inDCM (200 mL each)) and reverse phase HPLC (YMC ODS-A 150×20 mm, 5 μm, 25mL per min, gradient 20% to 80% (over 12 min) then 100% (3 min) MeOH in10% MeOH/water) to give 1,3-thiazol-2-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(51.8 mg, 4.0%) as a white solid.

Analytical HPLC: purity 99.5% (System B, R_(T)=3.81 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.27 min), ES⁺: 307.1 [MH]⁺; HRMScalculated for C₁₄H₁₈N₄O₂S: 306.1150. found 306.1153.

Example 22 (5-Methylisoxazol-3-yl)methyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]-pyridine-5-carboxylate

5-Methylisoxazole-3-methanol (1.64 g, 14.5 mmol) was dissolved in DCM(10 mL) at 0° C. and NMM (1.47 g, 1.40 mL, 14.5 mmol) and 4-nitrophenylchloroformate (2.93 g, 14.5 mmol) were added. The reaction mixture wasstirred at room temperature for 18 h. A solution of Intermediate 1 (1.87g, 3.60 mmol) in DCM (20 mL) and DIPEA (1.87 g, 2.52 mL, 14.5 mmol) wasadded and the resulting solution was stirred for 3 d and concentrated invacuo. The residue was dissolved in MeOH (8 mL) and 1 M aq NaOH solution(6 mL) and the reaction mixture was stirred for 18 h and concentrated invacuo. The residue was dissolved in EtOAc (100 mL) and the organic layerwas washed with 1 M aq Na₂CO₃ solution (6×100 mL), dried (MgSO₄) andconcentrated in vacuo. The residue was purified by reverse phase columnchromatography (LiChroprep RP-18, 40-63 μm, 460×26 mm (100 g), 30 mL permin, gradient 0% to 20% (over 5 min) to 90% (over 40 min) MeOH in water)and reverse phase HPLC (YMC ODS-A 150×20 mm, 5 μm, 25 mL per min,gradient 40% to 80% (over 7 min) then 100% (3 min) MeOH in 10%MeOH/water) to give (5-methylisoxazol-3-yl)methyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(107 mg, 9.7%) as a colourless gum.

Analytical HPLC: purity 99.5% (System B, R_(T)=4.09 min); AnalyticalLCMS: purity 100% (System B, R_(T)=4.51 min), ES⁺: 305.2 [MH]⁺; HRMScalculated for C₁₅H₂₀N₄O₃: 304.1535. found 304.1538.

Example 23 [(2S)-1-Methylpyrrolidin-2-yl]methyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

NaH (0.19 g, 5.00 mmol, 60% dispersion in mineral oil) was suspended inTHF (10 mL) at 0° C. and (S)—N-methylpyrrolidine-2-methanol (0.47 mL,4.80 mmol) was added. The suspension was stirred at 0° C. for 30 min andadded to a solution of Intermediate 2 (1.33 g, 4.00 mmol) in THF (10 mL)and the reaction mixture was stirred at room temperature. An additionalsuch portion of NaH and N-methylpyrrolidine methanol in THF was addedafter 8 h. After 18 h the reaction mixture was quenched with water (10mL) and the solvents were removed in vacuo. The residue was dissolved inEtOAc (100 mL), washed with 1 M aq Na₂CO₃ solution (4×100 mL), dried(MgSO₄) and the solvents were removed in vacuo. The residue was purifiedby column chromatography (normal phase, 20 g, Strata SI-1, silicagigatube, DCM (200 mL) followed by 2%, 4%, 5%, 10%, and 20% MeOH in DCM(200 mL)) and reverse phase HPLC (Phenomenex Synergi, RP-Hydro 150×10mm, 10 μm, 15 mL per min, gradient 0% to 60% (over 12 min) to 100% (over3 min) MeOH in water [1% formic acid]). The residue was de-salted usingK₂CO₃ in DCM to give [(2S)-1-methylpyrrolidin-2-yl]methyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(52.1 mg, 4.2%) as a colourless gum.

Analytical HPLC: purity 100% (System B, R_(T)=3.09 min); AnalyticalLCMS: purity 100% (System B, R_(T)=3.44 min), ES⁺: 307.1 [MH]⁺; HRMScalculated for C₁₆H₂₆N₄O₂: 306.2056. found 306.2068.

Example 24 (3R)-1-methylpyrrolidin-3-yl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

NaH (0.19 g, 5.00 mmol, 60% dispersion in mineral oil) was suspended inTHF (10 mL) at 0° C. and (R)-1-methylpyrrolidin-3-ol (0.47 mL, 4.00mmol) was added. The suspension was stirred at 0° C. for 30 min andadded to a solution of Intermediate 2 (1.33 g, 4.00 mmol) in THF (10 mL)and the reaction mixture was stirred at room temperature. Two additionalsuch portions of NaH and (R)-1-methylpyrrolidin-3-ol in THF were addedafter 18 and 26 h, respectively. After 44 h the reaction mixture wasquenched with water (10 mL) and the solvents were removed in vacuo. Theresidue was dissolved in EtOAc (100 mL), washed with 1 M aq Na₂CO₃solution (4×100 mL), dried (MgSO₄) and the solvents were removed invacuo. The residue was purified by column chromatography (normal phase,20 g, Strata SI-1, silica gigatube, DCM (200 ml) followed by 2%, 4%, 5%,10% and 20% MeOH in DCM (200 mL)) and reverse phase HPLC (PhenomenexSynergi, RP-Hydro 150×10 mm, 10 μm, 15 mL per min, gradient 0% to 30%(over 12 min) to 100% (over 3 min) MeOH in water [1% formic acid]). Theresidue was de-salted using K₂CO₃ in DCM to give(3R)-1-methylpyrrolidin-3-yl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo-[4,5-c]pyridine-5-carboxylate(32.3 mg, 2.7%) as a colourless gum.

Analytical HPLC: purity 100% (System B, R_(T)=2.99 min); AnalyticalLCMS: purity 100% (System B, R_(T)=3.36 min), ES⁺: 293.1 [MH]⁺; HRMScalculated for C₁₅H₂₄N₄O₂: 292.1899. found 292.1910.

Example 25 Oxetan-2-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

2-Hydroxymethyloxetane (0.71 g, 8.10 mmol) was dissolved in DCM (10 mL)at 0° C. and NMM (0.89 mL, 8.10 mmol) and 4-nitrophenyl chloroformate(1.63 g, 8.10 mmol) were added. The reaction mixture was stirred at roomtemperature for 5 h. A solution of Intermediate 1 (1.16 g, 3.90 mmol)and DIPEA (2.69 mL, 15.4 mmol) in DCM (20 mL) was added and theresulting solution was stirred for 18 h. The solvents were removed invacuo, the residue was dissolved in MeOH (10 mL) and 1 M aq NaOHsolution (10 mL) and the reaction mixture was stirred for 2 h andconcentrated in vacuo. The residue was dissolved in EtOAc (120 mL), theorganic layer was washed with 1M aq Na₂CO₃ solution (4×100 mL), dried(MgSO₄) and the solvents were removed in vacuo. The residue was purifiedby column chromatography (normal phase, 20 g, Strata SI-1, silicagigatube, DCM (200 ml) followed by 2%, 4% and 5% MeOH in DCM (200 mL))and reverse phase HPLC (YMC ODS-A 100×20 mm, 5 μm, 25 mL per min,gradient 20% to 100% (over 7 min) then 100% (3 min) MeOH in 10%MeOH/water) to give oxetan-2-ylmethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(93.4 mg, 8.7%) as a white solid.

Analytical HPLC: purity 100% (System B, R_(T)=3.58 min); AnalyticalLCMS: purity 100% (System B, R_(T)=3.84 min), ES⁺: 280.1 [MH]⁺; HRMScalculated for C₁₄H₂₁N₃O₃: 279.1583. found 279.1594.

Example 26 2-(Pyridin-3-yloxy)ethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate

2-(3-Pyridyloxy)ethanol (0.62 g, 4.40 mmol) was dissolved in DCM (10.0mL) at 0° C. and NMM (0.50 mL, 4.40 mmol) and 4-nitrophenylchloroformate (0.90 g, 4.40 mmol) were added. The reaction mixture wasstirred at room temperature for 5 h. A solution of Intermediate 1 (0.35g, 2.10 mmol) and DIPEA (1.10 g, 1.50 mL, 8.50 mmol) in DCM (20 mL) wasadded and the resulting solution was stirred for 3 d. The solvents wereremoved in vacuo, the residue was dissolved in MeOH (4 mL) and 1 M aqNaOH solution (4 mL) and the reaction mixture was stirred for 2 h andconcentrated in vacuo. The residue was dissolved in EtOAc (60 mL), theorganic layer was washed with 1 M aq Na₂CO₃ solution (5×40 mL), dried(MgSO₄) and the solvents were removed in vacuo. The residue was purifiedby column chromatography (normal phase, 20 g, Strata SI-1, silicagigatube, DCM (200 mL) followed by 2%, 4%, 5% and 10% MeOH in DCM (200mL)) and reverse phase HPLC (YMC ODS-A 100×20 mm, 5 μm, 25 mL per min,gradient 0% to 40% (over 7 min) then 100% (3 min) MeOH in 10%MeOH/water) to give 2-(pyridin-3-yloxy)ethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(7.4 mg, 1%) as a white solid.

Analytical HPLC: purity 99.4% (System B, R_(T)=3.21 min); AnalyticalLCMS: purity 100% (System B, R_(T)=3.20 min), ES⁺: 331.5 [MH]⁺; HRMScalculated for C₁₇H₂₂N₄O₃: 330.1692. found 330.1701.

Example 27 2-(2,2,2-Trifluoroethoxyl)ethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]-pyridine-5-carboxylate

2-(2,2,2-Trifluoroethoxyl)ethanol (0.57 mL, 3.60 mmol) was dissolved inTHF (5 mL), NaH (146 mg, 60% dispersion in mineral oil, 3.60 mmol) wasadded and the reaction mixture was stirred for 10 min. 4-Nitrophenylchloroformate (726 mg, 3.60 mmol) was added and the reaction mixture wasstirred for 16 h. Intermediate 1 (297 mg, 1.80 mmol) was dissolved inTHF (5 mL) and added to the reaction mixture which was stirred at roomtemperature. Three additional such portions of NaH,2-(2,2,2-trifluoroethoxyl)ethanol and 4-nitrophenyl chloroformate in THFwere added after 8, 24 and 32 h, respectively. After 104 h the reactionmixture was quenched with water (10 mL) and the solvents were removed invacuo. The residue was dissolved in MeOH (10 mL) and 1 M aq NaOHsolution (6 mL) and stirred for 1.5 h. The solvents were removed invacuo and the residue dissolved in EtOAc (100 mL). The organic layer waswashed with 1 M aq Na₂CO₃ solution (6×50 mL), brine (2×50 mL), dried(MgSO₄) and the solvents were removed in vacuo. The residue was purifiedby reverse phase HPLC (Phenomenex Synergi, RP-Hydro 150×10 mm, 10 μm, 15mL per min, gradient 0% to 50% (over 12 min) to 100% (over 3 min) MeOHin water to give 2-(2,2,2-trifluoroethoxyl)ethyl4-isopropyl-1,4,6,7-tetrahydro-5H-imidazo[4,5-c]pyridine-5-carboxylate(3 mg, 0.5%) as a pale yellow gum.

Analytical HPLC: purity 99.3% (System B, R_(T)=4.49 min); AnalyticalLCMS: purity 97.1% (System B, R_(T)=4.50 min), ES⁺: 336.5 [MH]⁺; HRMScalculated for C₁₄H₂₀F₃N₃O₃: 335.1457. found 335.1467.

Biological Tests

Biological Assay of the SSAO Enzyme Inhibitors

All assays were performed in room temperature with purifiedrecombinantly expressed human SSAO. Enzyme was prepared essentially asdescribed in Öhman et al. (Protein Expression and Purification 2006, 46,321-331). The enzyme activity was measured with benzylamine as substrateand utilized the production of hydrogen peroxide for detection. In ahorseradish peroxidise (HRP) coupled reaction, hydrogen peroxideoxidation of 10-acetyl-3,7-dihydroxyphenoxazine produced resorufin,which is a highly fluorescent compound (Zhout and Panchuk-Voloshina.Analytical Biochemistry 1997, 253, 169-174; Amplex® Red HydrogenPeroxide/peroxidise Assay kit, Invitrogen A22188).

Briefly, test compounds were dissolved in dimethyl sulfoxide (DMSO) to aconcentration of 10 mM. Dose-response measurements were assayed byeither creating 1:10 serial dilutions in DMSO to produce a 7 point curveor by making 1:3 serial dilutions in DMSO to produce 11 point curves.The top concentrations were adjusted depending on the potency of thecompounds and subsequent dilution in reaction buffer (50 mM sodiumphosphate, pH 7.4) yielded a final DMSO concentration ≦2%. Enzyme andcompounds were set to pre-incubate in flat-bottomed microtiter platesfor approximately 60 minutes before initiating the reaction by additionof a mixture of HRP, benzylamine and Amplex reagent. Fluorescenceintensity was then measured at several time points (15 minutes, 20minutes and 30 minutes) exciting at 544 nm and reading the emission at590 nm). Final concentrations of the reagents in the assay wells were:SSAO enzyme 2 μg/ml, benzylamine 100 μM, Amplex reagent 20 μM, HRP 0.1U/mL and varying concentrations of test compound. The inhibition wasmeasured as % decrease of the signal compared to a control withoutinhibitor (only diluted DMSO). The background signal from a samplecontaining no SSAO enzyme was subtracted from all data points. Data wasfitted to a four parameter logistic model and IC₅₀ values werecalculated using the GraphPad Prism 4 or XLfit 4 programs.

The exemplified compounds of the invention generally had an IC₅₀ valueof 1-1000 nM. Obtained IC₅₀ values for representative compounds areshown in the table below:

Compound IC₅₀ (nM) Example 7 34 Example 14 48 Example 17 91

The invention claimed is:
 1. A compound of formula (I),

or a pharmaceutically acceptable salt, solvate, hydrate, geometricalisomer, tautomer, optical isomer or N-oxide thereof, wherein: R¹ isselected from: (a) hydrogen, (b) C₁₋₆-alkyl, and (c) —NR^(4A)R^(4B); R²is selected from: (a) hydrogen, (b) —C(O)OMe, (c) —C(O)NH₂, and (d)—C(O)NHMe; R³ is selected from: (a) C₁₋₆-alkyl, (b) halo-C₁₋₆-alkyl, (c)hydroxy-C₁₋₆-alkyl, (d) C₁₋₆-alkoxy-C₁₋₆-alkyl, (e)halo-C₁₋₆-alkoxy-C₁₋₆-alkyl, (f) N(R^(4A)R^(4B))—C₁₋₆-alkyl, (g)C₆₋₁₀-aryl-C₁₋₄-alkyl, (h) heteroaryl-C₁₋₄-alkyl, (i)C₆₋₁₀-aryloxy-C₁₋₄-alkyl, (j) heteroaryloxy-C₁₋₄-alkyl, (k)C₃₋₈-cycloalkyl, (l) C₃₋₈-cycloalkyl-C₁₋₄-alkyl, (m) heterocyclyl, and(n) heterocyclyl-C₁₋₄-alkyl, wherein any aryl or heteroaryl residue isoptionally substituted with one more substituents independently selectedfrom halogen, hydroxy, cyano, nitro, CF₃, C₁₋₄-alkyl, C₁₋₄-alkoxy and—NR^(4A)R^(4B), and wherein any cycloalkyl or heterocyclyl residue isoptionally substituted with one or more substituents independentlyselected from halogen, hydroxy, C₁₋₄-alkyl, C₁₋₄-alkoxy and—NR^(4A)R^(4B); R^(4A) and R^(4B) are each independently selected from:(a) hydrogen, (b) C₁₋₆-alkyl, and (c) C₁₋₆-acyl provided that when R¹and R² are hydrogen, then R³ is not benzyl.
 2. A compound according toclaim 1, wherein R¹ is H.
 3. A compound according to claim 1, wherein R³is selected from halo-C₁₋₂-alkyl, halo-C₁₋₂-alkoxy-C₁₋₂-alkyl,di(C₁₋₂-alkyl)amino-C₁₋₂-alkyl, phenyl-C₁₋₂-alkyl, phenoxy-C₁₋₂-alkyl,C₅₋₆-heteroaryl-C₁₋₂-alkyl, C₅₋₆-heteroaryloxy-C₁₋₂-alkyl, heterocyclyland heterocyclyl-C₁₋₂-alkyl, and wherein any phenyl, heteroaryl orheterocyclyl residue is optionally substituted with one or twosubstituents independently selected from halogen and C₁₋₂-alkyl.
 4. Apharmaceutical formulation containing a compound according to claim 1 asactive ingredient, in combination with a pharmaceutically acceptablediluent or carrier.
 5. A compound of formula (I),

or a pharmaceutically acceptable salt, solvate, hydrate, geometricalisomer, tautomer, optical isomer or N-oxide thereof, wherein: R¹ isselected from: (a) hydrogen, (b) C₁₋₆-alkyl, and (c) —NR^(4A)R^(4B); R²is selected from: (a) hydrogen, (b) —C(O)OMe, (c) —C(O)NH₂, and (d)—C(O)NHMe; R³ is selected from: (a) halo-C₁₋₄-alkyl, (b)halo-C₁₋₄-alkoxy-C₁₋₄-alkyl, (c) di(C₁₋₄-alkyl)-amino-C₁₋₄-alkyl, (d)C₆₋₁₀-aryl-C₁₋₄-alkyl, (e) C₆₋₁₀-aryloxy-C₁₋₄-alkyl, (f)heteroaryl-C₁₋₄-alkyl, (g) heteroaryloxy-C₁₋₄-alkyl, and (h)heterocyclyl and heterocyclyl-C₁₋₄-alkyl, wherein any aryl, heteroarylor heterocyclyl residue is optionally substituted with one or twosubstituents independently selected from halogen and C₁₋₄-alkyl; andR^(4A) and R^(4B) are each independently selected from: (d) hydrogen,(e) C₁₋₆-alkyl, and (f) C₁₋₆-acyl provided that when R¹ and R² arehydrogen, then R³ is not benzyl.
 6. A compound according to claim 5,wherein R¹ is H.
 7. The compound according to claim 5, wherein R³ is2,2,2-trichloroethyl, 2-chloro-2,2-difluoroethyl,2,2,2-trifluoroethoxyethyl, dimethylaminoethyl, benzyl, pyridinylmethyl,pyrazinylmethyl, thiazolylmethyl, isoxazolylmethyl, phenoxyethyl,pyridinyloxyethyl, tetrahydrofuranyl, tetrahydrofuranylmethyl,pyrrolidinyl, pyrrolidinylmethyl or oxetanylmethyl, wherein any phenyl,heteroaryl or heterocyclyl residue is optionally monosubstituted withhalogen or methyl.
 8. A pharmaceutical formulation containing a compoundaccording to claim 5 as active ingredient, in combination with apharmaceutically acceptable diluent or carrier.